Season 1 Season 2 Season 3 Season 4 Season 5 Season 6 Season 7 Season 8 Season 9 Season 10 Season 11

The Big Bang Theory is centered on five characters living in Pasadena, California: roommates Leonard Hofstadter and Sheldon Cooper; Penny, a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon’s equally geeky and socially awkward friends and co-workers, mechanical engineer Howard Wolowitz and astrophysicist Raj Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny’s social skills and common sense.

Season 1

Pilot - The Big Bang Theory

Pilot - The Big Bang Theory

Season 1 | Episode 1 Brilliant physicist roommates Leonard and Sheldon meet their new neighbor Penny, who begins showing them that as much as they know about science, they know little about actual living.

The Big Bran Hypothesis - The Big Bang Theory

The Big Bran Hypothesis - The Big Bang Theory

Season 1 | Episode 2 Leonard volunteers to sign for a package in an attempt to make a good impression on Penny, but when he enlists Sheldon for help, his attempt at chivalry goes terribly awry.

The Fuzzy Boots Corollary - The Big Bang Theory

The Fuzzy Boots Corollary - The Big Bang Theory

Season 1 | Episode 3 Leonard asks a woman out after he finds out that Penny is seeing someone.

The Luminous Fish Effect - The Big Bang Theory

The Luminous Fish Effect - The Big Bang Theory

Season 1 | Episode 4 Sheldon's getting fired forces him to explore what life has to offer outside physics, leaving Leonard to take drastic action to snap his friend out of his funk.

The Hamburger Postulate - The Big Bang Theory

The Hamburger Postulate - The Big Bang Theory

Season 1 | Episode 5 Fearing he's wasting his time on Penny, Leonard ends up making a connection with Leslie.

The Middle-Earth Paradigm - The Big Bang Theory

The Middle-Earth Paradigm - The Big Bang Theory

Season 1 | Episode 6 Penny hosts a Halloween party, putting Leonard, Sheldon, Wolowitz, and Koothrappali through a new test of their social skills.

The Dumpling Paradox - The Big Bang Theory

The Dumpling Paradox - The Big Bang Theory

Season 1 | Episode 7 With Wolowitz AWOL with one of her friends, Penny's recruited to fill in for him on the guys' Halo team

The Grasshopper Experiment - The Big Bang Theory

The Grasshopper Experiment - The Big Bang Theory

Season 1 | Episode 8 Raj's parents set him up on a blind date, but just when he discovers he can talk to her, she shows interest in Sheldon.

The Cooper-Hofstadter Polarization - The Big Bang Theory

The Cooper-Hofstadter Polarization - The Big Bang Theory

Season 1 | Episode 9 When they're invited to present at a physics conference, Sheldon's reluctance to share the credit leads to a tiff between him and Leonard, and Penny's intervention only exacerbates the situation.

The Loobenfeld Decay - The Big Bang Theory

The Loobenfeld Decay - The Big Bang Theory

Season 1 | Episode 10 Leonard and Sheldon each lie to avoid seeing Penny's concert, but Sheldon's is a bit too complicated for his own good.

The Pancake Batter Anomaly - The Big Bang Theory

The Pancake Batter Anomaly - The Big Bang Theory

Season 1 | Episode 11 With his friends knowing how sour he acts when sick—and avoiding him as a result—Sheldon is nursed by Penny, who hasn't a clue what she's in for.

The Jerusalem Duality - The Big Bang Theory

The Jerusalem Duality - The Big Bang Theory

Season 1 | Episode 12 With Sheldon rattled over meeting Dennis, a 15-year-old physicist who's smarter than he, Leonard helps him look for a way to debunk Dennis's research.

The Bat Jar Conjecture - The Big Bang Theory

The Bat Jar Conjecture - The Big Bang Theory

Season 1 | Episode 13 Sheldon finds himself booted from the gang's Physics Bowl team and replaced with Leslie, so he forms his own team, hoping to prove he's superior.

The Nerdvana Annihilation - The Big Bang Theory

The Nerdvana Annihilation - The Big Bang Theory

Season 1 | Episode 14 When delivery of another collectible leads to Penny's lashing out at Leonard, he decides it's time to give up his habit, much to his friends' protestation.

The Pork Chop Indeterminacy - The Big Bang Theory

The Pork Chop Indeterminacy - The Big Bang Theory

Season 1 | Episode 15 The rest of the gang fall for Sheldon's twin sister, and Leonard's plan to win her heart is derailed when Sheldon declares he'll be the one to decide who can date her.

The Peanut Reaction - The Big Bang Theory

The Peanut Reaction - The Big Bang Theory

Season 1 | Episode 16 Penny wants to throw a surprise party for Leonard, but Sheldon's indulgence at an electronics store throws her off-track.

The Tangerine Factor - The Big Bang Theory

The Tangerine Factor - The Big Bang Theory

Season 1 | Episode 17 Penny's break-up spurs Leonard to summon the courage to ask her out, and each goes to Sheldon for advice on their upcoming date.

Season 2

The Bad Fish Paradigm - The Big Bang Theory

The Bad Fish Paradigm - The Big Bang Theory

Season 2 | Episode 1 Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.

The Codpiece Topology - The Big Bang Theory

The Codpiece Topology - The Big Bang Theory

Season 2 | Episode 2 A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.

The Barbarian Sublimation - The Big Bang Theory

The Barbarian Sublimation - The Big Bang Theory

Season 2 | Episode 3 Sheldon creates a monster when he introduces Penny to online gaming.

The Griffin Equivalency - The Big Bang Theory

The Griffin Equivalency - The Big Bang Theory

Season 2 | Episode 4 Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.

The Euclid Alternative - The Big Bang Theory

The Euclid Alternative - The Big Bang Theory

Season 2 | Episode 5 Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.

The Cooper-Nowitzki Theorem - The Big Bang Theory

The Cooper-Nowitzki Theorem - The Big Bang Theory

Season 2 | Episode 6 Sheldon and the gang are confused when a young grad student is attracted to him.

The Panty Piñata Polarization - The Big Bang Theory

The Panty Piñata Polarization - The Big Bang Theory

Season 2 | Episode 7 When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.

The Lizard-Spock Expansion - The Big Bang Theory

The Lizard-Spock Expansion - The Big Bang Theory

Season 2 | Episode 8 Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.

The White Asparagus Triangulation - The Big Bang Theory

The White Asparagus Triangulation - The Big Bang Theory

Season 2 | Episode 9 Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.

The Vartabedian Conundrum - The Big Bang Theory

The Vartabedian Conundrum - The Big Bang Theory

Season 2 | Episode 10 Leonard asks Penny for advice when his new relationship starts moving too fast.

The Bath Item Gift Hypothesis - The Big Bang Theory

The Bath Item Gift Hypothesis - The Big Bang Theory

Season 2 | Episode 11 Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.

The Killer Robot Instability - The Big Bang Theory

The Killer Robot Instability - The Big Bang Theory

Season 2 | Episode 12 Penny's criticism of Wolowitz's romantic life pushes him into depression and AWOL for a fighting robot battle the rest of guys are depending on him for.

The Friendship Algorithm - The Big Bang Theory

The Friendship Algorithm - The Big Bang Theory

Season 2 | Episode 13 Sheldon creates a scientific procedure for making friends.

The Financial Permeability - The Big Bang Theory

The Financial Permeability - The Big Bang Theory

Season 2 | Episode 14 Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.

The Maternal Capacitance - The Big Bang Theory

The Maternal Capacitance - The Big Bang Theory

Season 2 | Episode 15 Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.

The Cushion Saturation - The Big Bang Theory

The Cushion Saturation - The Big Bang Theory

Season 2 | Episode 16 A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.

The Terminator Decoupling - The Big Bang Theory

The Terminator Decoupling - The Big Bang Theory

Season 2 | Episode 17 Leonard, Sheldon and Wolowitz are ecstatic to learn that a famous science-fiction actress (Summer Glau) is on board the train they are taking to San Francisco.

The Work Song Nanocluster - The Big Bang Theory

The Work Song Nanocluster - The Big Bang Theory

Season 2 | Episode 18 Penny's home business turns into a complete nightmare when Sheldon takes over.

The Dead Hooker Juxtaposition - The Big Bang Theory

The Dead Hooker Juxtaposition - The Big Bang Theory

Season 2 | Episode 19 Penny squares off with a new beautiful female neighbor who may become the building's "new Penny."

The Hofstadter Isotope - The Big Bang Theory

The Hofstadter Isotope - The Big Bang Theory

Season 2 | Episode 20 A fellow comic book enthusiast's hitting on Penny leads to Leonard and Howard going to a bar's Ladies' Night.

The Vegas Renormalization - The Big Bang Theory

The Vegas Renormalization - The Big Bang Theory

Season 2 | Episode 21 Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas, and Sheldon becomes locked out of his apartment and must stay with Penny.

The Classified Materials Turbulence - The Big Bang Theory

The Classified Materials Turbulence - The Big Bang Theory

Season 2 | Episode 22 Penny's second date with Stuart sees her making a comment that gives Leonard new hope for a relationship with her. Wolowitz realizes there's a crucial error in a NASA project he's working on.

The Monopolar Expedition - The Big Bang Theory

The Monopolar Expedition - The Big Bang Theory

Season 2 | Episode 23 The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.

Season 3

The Electric Can Opener Fluctuation - The Big Bang Theory

The Electric Can Opener Fluctuation - The Big Bang Theory

Season 3 | Episode 1 When Sheldon learns the guys tampered with his expedition data he got from the arctic, he leaves to Texas in disgrace. This results in the guys following him, which threatens Leonard's hope for some romantic time with Penny and the guys' friendship with Sheldon.

The Jiminy Conjecture - The Big Bang Theory

The Jiminy Conjecture - The Big Bang Theory

Season 3 | Episode 2 Leonard and Penny struggle to recover from an awkward first hookup while Sheldon and Howard stake their best comic books on a bet to determine the species of a cricket.

The Gothowitz Deviation - The Big Bang Theory

The Gothowitz Deviation - The Big Bang Theory

Season 3 | Episode 3 Howard and Raj visit a Goth nightclub to pick up women while Sheldon attempts to build a better Penny using chocolate-based behavior modification.

The Pirate Solution - The Big Bang Theory

The Pirate Solution - The Big Bang Theory

Season 3 | Episode 4 Raj must find a new job or be sent back to India, but Sheldon has a solution, which leaves Leonard and Penny dealing with Howard as a third wheel.

The Creepy Candy Coating Corollary - The Big Bang Theory

The Creepy Candy Coating Corollary - The Big Bang Theory

Season 3 | Episode 5 After overhearing that Wil Wheaton is entering a trading-card competition, Sheldon decides to enter it himself. Meanwhile, Penny sets up one of her friends on a date with Wolowitz.

The Cornhusker Vortex - The Big Bang Theory

The Cornhusker Vortex - The Big Bang Theory

Season 3 | Episode 6 Sheldon becomes Leonard's teacher in order to understand football, while an incident with flying a kite threatens Howard and Raj's friendship.

The Guitarist Amplification - The Big Bang Theory

The Guitarist Amplification - The Big Bang Theory

Season 3 | Episode 7 A squabble between Leonard and Penny sees Sheldon playing mediator, though out of his own incovenience from the sitiation rather than altruism.

The Adhesive Duck Deficiency - The Big Bang Theory

The Adhesive Duck Deficiency - The Big Bang Theory

Season 3 | Episode 8 With Leonard, Howard and Raj away camping in the desert, an injured Penny has only Sheldon to rely on.

The Vengeance Formulation - The Big Bang Theory

The Vengeance Formulation - The Big Bang Theory

Season 3 | Episode 9 After he's humiliated on National Public Radio, Sheldon vows to destroy Kripke, while Wolowitz tries not to destroy his new relationship with Bernadette.

The Gorilla Experiment - The Big Bang Theory

The Gorilla Experiment - The Big Bang Theory

Season 3 | Episode 10 Penny gets help from Sheldon in order to understand what Leonard's work is, while Wolowitz develops a jealousy when Leonard starts hanging out with his new girlfriend.

The Maternal Congruence - The Big Bang Theory

The Maternal Congruence - The Big Bang Theory

Season 3 | Episode 11 A Christmas visit from his mother has Leonard discovering she's kept a lot of news from him that she shares with Sheldon and worrying if she'll approve of his romance with Penny.

The Psychic Vortex - The Big Bang Theory

The Psychic Vortex - The Big Bang Theory

Season 3 | Episode 12 Leonard is aghast to find out a secret of Penny's: she believes in psychics. Meanwhile, Sheldon tries to assist Koothrappali in picking up a girl at a university mixer.

The Bozeman Reaction - The Big Bang Theory

The Bozeman Reaction - The Big Bang Theory

Season 3 | Episode 13 When their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system.

The Einstein Approximation - The Big Bang Theory

The Einstein Approximation - The Big Bang Theory

Season 3 | Episode 14 Sheldon's search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.

The Large Hadron Collision - The Big Bang Theory

The Large Hadron Collision - The Big Bang Theory

Season 3 | Episode 15 Leonard can only bring one guest on a trip to see CERN's Large Hadron Collider (the world's largest and highest energy particle accelerator) in Switzerland on Valentine's Day.

The Excelsior Acquisition - The Big Bang Theory

The Excelsior Acquisition - The Big Bang Theory

Season 3 | Episode 16 Sheldon winds up in traffic court when he gets a ticket because of Penny.

The Precious Fragmentation - The Big Bang Theory

The Precious Fragmentation - The Big Bang Theory

Season 3 | Episode 17 When the guys find a ring from "The Lord of the Rings" at a garage sale, it threatens to tear them apart.

The Pants Alternative - The Big Bang Theory

The Pants Alternative - The Big Bang Theory

Season 3 | Episode 18 Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.

The Wheaton Recurrence - The Big Bang Theory

The Wheaton Recurrence - The Big Bang Theory

Season 3 | Episode 19 A fight between Leonard and Penny threatens their relationship, while Sheldon battles Wil Wheaton in bowling.

The Spaghetti Catalyst - The Big Bang Theory

The Spaghetti Catalyst - The Big Bang Theory

Season 3 | Episode 20 When Leonard and Penny aren't speaking, Sheldon goes to extremes to keep them both happy.

The Plimpton Stimulation - The Big Bang Theory

The Plimpton Stimulation - The Big Bang Theory

Season 3 | Episode 21 Leonard and Sheldon compete for the attention of a famous female physicist.

The Staircase Implementation - The Big Bang Theory

The Staircase Implementation - The Big Bang Theory

Season 3 | Episode 22 Leonard tells Penny about how he met Sheldon for the first time...and what happened to the elevator.

The Lunar Excitation - The Big Bang Theory

The Lunar Excitation - The Big Bang Theory

Season 3 | Episode 23 While Penny worries that dating Leonard has ruined her for normal guys, Wolowitz and Koothrappali search for Sheldon's perfect match online.

Season 4

The Robotic Manipulation - The Big Bang Theory

The Robotic Manipulation - The Big Bang Theory

Season 4 | Episode 1 Penny tags along on Sheldon's first ever date; Wolowitz finds a new use for a robotic arm.

The Cruciferous Vegetable Amplification - The Big Bang Theory

The Cruciferous Vegetable Amplification - The Big Bang Theory

Season 4 | Episode 2 Realizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.

The Zazzy Substitution - The Big Bang Theory

The Zazzy Substitution - The Big Bang Theory

Season 4 | Episode 3 The guys are concerned as Sheldon searches for an alternative to human companionship.

The Hot Troll Deviation - The Big Bang Theory

The Hot Troll Deviation - The Big Bang Theory

Season 4 | Episode 4 An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.

The Desperation Emanation - The Big Bang Theory

The Desperation Emanation - The Big Bang Theory

Season 4 | Episode 5 Leonard realizes he’s the only one without a girlfriend, while Sheldon wants to get rid of his.

The Irish Pub Formulation - The Big Bang Theory

The Irish Pub Formulation - The Big Bang Theory

Season 4 | Episode 6 Leonard keeps an affair a secret from Sheldon, Howard and Raj.

The Apology Insufficiency - The Big Bang Theory

The Apology Insufficiency - The Big Bang Theory

Season 4 | Episode 7 Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.

The 21-second Excitation - The Big Bang Theory

The 21-second Excitation - The Big Bang Theory

Season 4 | Episode 8 While the guys camp in line for a long-awaited movie screening, Penny and Bernadette invite Amy to her first slumber party.

The Boyfriend Complexity - The Big Bang Theory

The Boyfriend Complexity - The Big Bang Theory

Season 4 | Episode 9 Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.

The Alien Parasite Hypothesis - The Big Bang Theory

The Alien Parasite Hypothesis - The Big Bang Theory

Season 4 | Episode 10 Amy finds she has sexual feelings for Penny's ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.

The Justice League Recombination - The Big Bang Theory

The Justice League Recombination - The Big Bang Theory

Season 4 | Episode 11 The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.

The Bus Pants Utilization - The Big Bang Theory

The Bus Pants Utilization - The Big Bang Theory

Season 4 | Episode 12 Leonard's idea for a smartphone app derails his friendship with Sheldon.

The Love Car Displacement - The Big Bang Theory

The Love Car Displacement - The Big Bang Theory

Season 4 | Episode 13 Bernadette runs into her ex-boyfriend while attending a science event with Wolowitz.

The Thespian Catalyst - The Big Bang Theory

The Thespian Catalyst - The Big Bang Theory

Season 4 | Episode 14 Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friend's girlfriend.

The Benefactor Factor - The Big Bang Theory

The Benefactor Factor - The Big Bang Theory

Season 4 | Episode 15 A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.

The Cohabitation Formulation - The Big Bang Theory

The Cohabitation Formulation - The Big Bang Theory

Season 4 | Episode 16 As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj's sister.

The Toast Derivation - The Big Bang Theory

The Toast Derivation - The Big Bang Theory

Season 4 | Episode 17 Sheldon becomes concerned when everybody begins to hang out at Raj's apartment and discovers Leonard is the center of the group.

The Prestidigitation Approximation - The Big Bang Theory

The Prestidigitation Approximation - The Big Bang Theory

Season 4 | Episode 18 Sheldon is baffled by Wolowitz's magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.

The Zarnecki Incursion - The Big Bang Theory

The Zarnecki Incursion - The Big Bang Theory

Season 4 | Episode 19 Sheldon's online-game account is hacked by Todd Zarnecki, who then proceeds to steal all his items prompting the guys to go on a quest to retrieve them. Penny, Bernadette and Amy discuss how Penny groomed Leonard to be willing to try various things and more adventurous boyfriend... for some other woman — Priya.

The Herb Garden Germination - The Big Bang Theory

The Herb Garden Germination - The Big Bang Theory

Season 4 | Episode 20 Sheldon and Amy decide to start several rumors about the others as a test. Meanwhile, Howard takes his relationship with Bernadette to even higher level.

The Agreement Dissection - The Big Bang Theory

The Agreement Dissection - The Big Bang Theory

Season 4 | Episode 21 When Leonard spends too much time in the shower with Priya, Sheldon charges Leonard with two violations of the roommate agreement. However, before he can get too far, Priya uses her skills as a lawyer to nullify the charges due to the agreement's vague wording, much to Sheldon's dismay. When the guys take advantage of Priya's skills in order to eat Greek food on pizza night, Sheldon goes to Penny, who invites him to a girls' night out with Amy and Bernadette, which Sheldon agrees to after Penny mentions that they may be talking trash about Priya. After the girls drink some cocktails, they decide to take Sheldon dancing, which Sheldon reluctantly goes along with. After dancing, Sheldon takes an intoxicated Amy back to her apartment and as well as talking about Priya, meets a monkey who is addicted to smoking cigarettes. Amy tells Sheldon not to give in to Priya's law skills, before kissing him and going to her bathroom to vomit.

The Wildebeest Implementation - The Big Bang Theory

The Wildebeest Implementation - The Big Bang Theory

Season 4 | Episode 22 Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.

The Engagement Reaction - The Big Bang Theory

The Engagement Reaction - The Big Bang Theory

Season 4 | Episode 23 When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.

The Roommate Transmogrification - The Big Bang Theory

The Roommate Transmogrification - The Big Bang Theory

Season 4 | Episode 24 When Bernadette receives her PhD, Wolowitz feels emasculated. Raj and Leonard swap places and Penny does something she's regrets.

Season 5

The Skank Reflex Analysis - The Big Bang Theory

The Skank Reflex Analysis - The Big Bang Theory

Season 5 | Episode 1 Penny is worried with how damaged her friendship with the guys will be in the aftermath of her sleeping with Raj while Sheldon becomes the leader of the paintball team.

The Infestation Hypothesis - The Big Bang Theory

The Infestation Hypothesis - The Big Bang Theory

Season 5 | Episode 2 A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

The Pulled Groin Extrapolation - The Big Bang Theory

The Pulled Groin Extrapolation - The Big Bang Theory

Season 5 | Episode 3 Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.

The Wiggly Finger Catalyst - The Big Bang Theory

The Wiggly Finger Catalyst - The Big Bang Theory

Season 5 | Episode 4 Penny plays Matchmaker for Raj, which results in him finding a girl he is comfortable talking to.

The Russian Rocket Reaction - The Big Bang Theory

The Russian Rocket Reaction - The Big Bang Theory

Season 5 | Episode 5 Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.

The Rhinitis Revelation - The Big Bang Theory

The Rhinitis Revelation - The Big Bang Theory

Season 5 | Episode 6 Sheldon's mother, Mary Cooper, comes to visit, but Sheldon is annoyed that she also spends time with the rest of the gang, instead of catering to his every demand.

The Good Guy Fluctuation - The Big Bang Theory

The Good Guy Fluctuation - The Big Bang Theory

Season 5 | Episode 7 A cute comic book artist puts Leonard and Priya’s relationship to the test, while Sheldon tries to scare the guys for Halloween.

The Isolation Permutation - The Big Bang Theory

The Isolation Permutation - The Big Bang Theory

Season 5 | Episode 8 Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.

The Ornithophobia Diffusion - The Big Bang Theory

The Ornithophobia Diffusion - The Big Bang Theory

Season 5 | Episode 9 Leonard and Penny try hanging out as friends on a 'non-date', but end up purposely ruining each others chances with perspective dates. Meanwhile, Sheldon enlists the help of Bernadette and Amy to overcome his fear of birds.

The Flaming Spittoon Acquisition - The Big Bang Theory

The Flaming Spittoon Acquisition - The Big Bang Theory

Season 5 | Episode 10 When Stuart asks Amy out on a date, Sheldon must confront his feelings and consider where his relationship with Amy is going.

The Speckerman Recurrence - The Big Bang Theory

The Speckerman Recurrence - The Big Bang Theory

Season 5 | Episode 11 Leonard must face his fears after being contacted by his high school tormentor.

The Shiny Trinket Maneuver - The Big Bang Theory

The Shiny Trinket Maneuver - The Big Bang Theory

Season 5 | Episode 12 Sheldon gets in trouble with Amy when he isn't impressed by her recent accomplishment, and Howard must come to grips with Bernadette's dislike of children.

The Recombination Hypothesis - The Big Bang Theory

The Recombination Hypothesis - The Big Bang Theory

Season 5 | Episode 13 Leonard, who broke up with Priya, asks Penny out to a spur-of the-moment romantic dinner for two, and the duo contemplates on their relationship.

The Beta Test Initiation - The Big Bang Theory

The Beta Test Initiation - The Big Bang Theory

Season 5 | Episode 14 Leonard and Penny deal with the idea of starting a relationship again and Raj finally finds a "woman" he can talk to without being drunk, in the form of Siri on his new phone. Meanwhile, Sheldon decides to start a YouTube series entitled "Sheldon Cooper presents Fun with Flags" with the help of Amy.

The Friendship Contraction - The Big Bang Theory

The Friendship Contraction - The Big Bang Theory

Season 5 | Episode 15 Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.

The Vacation Solution - The Big Bang Theory

The Vacation Solution - The Big Bang Theory

Season 5 | Episode 16 When Sheldon is forced to take his vacation, he goes to work with Amy in her neurobiology lab.

The Rothman Disintegration - The Big Bang Theory

The Rothman Disintegration - The Big Bang Theory

Season 5 | Episode 17 Penny is horrified when Amy gives her a gift: a huge, quite horrible painting of the two of them. With no good way to avoid displaying it, she only hangs it up when Amy is over. When Amy catches her taking the painting down, she's embarrassed and angry until Penny lies and says the gift made Bernadette jealous. When the deranged Professor Rothman is forced to retire, both Sheldon and Kripke vie for his office. President Siebert refuses to resolve the dispute, so Leonard arranges a one-on-one basketball game to decide (since they're both equally bad at sports). Neither one can even make a single basket, so they end up deciding by seeing who can bounce the ball the highest. Sheldon wins; unfortunately, the office is not what he'd hoped for: the thermostat is located in the office of a professor going through the hot flashes of menopause (thus Sheldon is too cold), the mockingbird outside his window is off-key with the annoying windchimes, the perpetually naked Professor Rothman refuses to vacate, and the Geology Department upstairs makes too much noise. Finally, Sheldon gets his head stuck in the wall in an existing hole, after which Leonard takes his picture before he goes for help.

The Werewolf Transformation - The Big Bang Theory

The Werewolf Transformation - The Big Bang Theory

Season 5 | Episode 18 Sheldon becomes agitated when his regular barber is out sick. Astronaut training causes Howard to reconsider wanting to go into space. Penny beats Leonard in chess, the first time she plays.

The Weekend Vortex - The Big Bang Theory

The Weekend Vortex - The Big Bang Theory

Season 5 | Episode 19 Sheldon must choose between joining Amy at her aunt's birthday party or playing videogames all weekend with the guys.

The Transporter Malfunction - The Big Bang Theory

The Transporter Malfunction - The Big Bang Theory

Season 5 | Episode 20 Penny buys Leonard and Sheldon “Star Trek” collectibles as a thank-you, leading Sheldon to be haunted by Mr. Spock. Meanwhile, Raj decides he has met the “Future Mrs. Koothrappali” after his parents set him up on a date.

The Hawking Excitation - The Big Bang Theory

The Hawking Excitation - The Big Bang Theory

Season 5 | Episode 21 When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

The Stag Convergence - The Big Bang Theory

The Stag Convergence - The Big Bang Theory

Season 5 | Episode 22 After the guys throw Howard a bachelor party, Bernadette reconsiders marrying him after learning about his sexual history.

The Launch Acceleration - The Big Bang Theory

The Launch Acceleration - The Big Bang Theory

Season 5 | Episode 23 When NASA moves up Howard's mission, he must face his fears and Bernadette's dad, thus putting the wedding plans in jeopardy. Meanwhile, Leonard says something surprising to Penny in the bedroom.

The Countdown Reflection - The Big Bang Theory

The Countdown Reflection - The Big Bang Theory

Season 5 | Episode 24 The fifth season ends with Howard and Bernadette deciding to get married before his NASA mission, causing the gang to scurry into overdrive in an effort to stage the wedding. NASA astronaut Mike Massimino has a cameo as himself.

Season 6

The Date Night Variable - The Big Bang Theory

The Date Night Variable - The Big Bang Theory

Season 6 | Episode 1 With his friends on dates, Raj must face his loneliness. Also, Wolowitz is caught in an argument between Bernadette and his mom, even while he’s in space

The Decoupling Fluctuation - The Big Bang Theory

The Decoupling Fluctuation - The Big Bang Theory

Season 6 | Episode 2 When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.

The Higgs Boson Observation - The Big Bang Theory

The Higgs Boson Observation - The Big Bang Theory

Season 6 | Episode 3 Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz.

The Re-Entry Minimization - The Big Bang Theory

The Re-Entry Minimization - The Big Bang Theory

Season 6 | Episode 4 When Wolowitz returns from space, he doesn’t get the hero’s welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.

The Holographic Excitation - The Big Bang Theory

The Holographic Excitation - The Big Bang Theory

Season 6 | Episode 5 The gang celebrates Halloween at Stuart’s comic book store. Meanwhile, Leonard seduces Penny with science.

The Extract Obliteration - The Big Bang Theory

The Extract Obliteration - The Big Bang Theory

Season 6 | Episode 6 Sheldon’s relationship with Stephen Hawking is threatened over a game of “Words with Friends,” and Penny secretly enrolls in a class at the local college.

The Habitation Configuration - The Big Bang Theory

The Habitation Configuration - The Big Bang Theory

Season 6 | Episode 7 Wolowitz struggles with moving out of his mother’s house. Meanwhile, Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.

The 43 Peculiarity - The Big Bang Theory

The 43 Peculiarity - The Big Bang Theory

Season 6 | Episode 8 Raj and Howard try to to figure out why Sheldon disappears at 2:45 every afternoon; jealousy arises in Penny and Leonard's relationship.

The Parking Spot Escalation - The Big Bang Theory

The Parking Spot Escalation - The Big Bang Theory

Season 6 | Episode 9 When the University reassigns Sheldon’s parking spot to Wolowitz, their fight affects the whole gang.

The Fish Guts Displacement - The Big Bang Theory

The Fish Guts Displacement - The Big Bang Theory

Season 6 | Episode 10 When Amy gets sick, Sheldon tries to nurse her back to health; Wolowitz and his father-in-law plan a fishing trip.

The Santa Simulation - The Big Bang Theory

The Santa Simulation - The Big Bang Theory

Season 6 | Episode 11 During a game, Sheldon revisits Christmas memories; Amy, Penny and Bernadette look for a date for Koothrappali.

The Egg Salad Equivalency - The Big Bang Theory

The Egg Salad Equivalency - The Big Bang Theory

Season 6 | Episode 12 When Sheldon is accused of sexual harassment, he ends up getting Raj, Leonard and Wolowitz in trouble.

The Bakersfield Expedition - The Big Bang Theory

The Bakersfield Expedition - The Big Bang Theory

Season 6 | Episode 13 As the guys don costumes and go on a road trip to a comic book convention, the ladies decide to stay home and try to interpret a comic book.

The Cooper/Kripke Inversion - The Big Bang Theory

The Cooper/Kripke Inversion - The Big Bang Theory

Season 6 | Episode 14 Sheldon faces a crisis of confidence when he is forced to work with his nemesis, Barry Kripke; Raj and Howard buy expensive action figures of themselves.

The Spoiler Alert Segmentation - The Big Bang Theory

The Spoiler Alert Segmentation - The Big Bang Theory

Season 6 | Episode 15 A fight between Sheldon and Leonard impacts Amy and Penny's living arrangements; while Howard is away, Raj helps Mrs. Wolowitz out.

The Tangible Affection Proof - The Big Bang Theory

The Tangible Affection Proof - The Big Bang Theory

Season 6 | Episode 16 The guys search for a perfect Valentine's Day gift for their significant others; Stuart and Raj host a "lonely people" party at the comic book store.

The Monster Isolation - The Big Bang Theory

The Monster Isolation - The Big Bang Theory

Season 6 | Episode 17 After a bad date, Koothrappali decides to never leave his apartment; Penny's acting skills impress Sheldon.

The Contractual Obligation Implementation - The Big Bang Theory

The Contractual Obligation Implementation - The Big Bang Theory

Season 6 | Episode 18 Leonard, Sheldon and Wolowitz talk to junior high girls about science-related careers; Raj plans a date with Lucy.

The Closet Reconfiguration - The Big Bang Theory

The Closet Reconfiguration - The Big Bang Theory

Season 6 | Episode 19 Howard considers whether or not he should open a letter from his father; Penny and Leonard host a "grown-up" cocktail party.

The Tenure Turbulence - The Big Bang Theory

The Tenure Turbulence - The Big Bang Theory

Season 6 | Episode 20 The girls get involved when Leonard, Sheldon and Raj compete for tenure at the University.

The Closure Alternative - The Big Bang Theory

The Closure Alternative - The Big Bang Theory

Season 6 | Episode 21 Amy tries to help Sheldon get over his compulsive need for closure when one of his favorite TV shows is canceled; Raj discovers a secret about Lucy.

The Proton Resurgence - The Big Bang Theory

The Proton Resurgence - The Big Bang Theory

Season 6 | Episode 22 Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform; Bernadette and Howard run into trouble while dog-sitting for Raj's pet.

The Love Spell Potential - The Big Bang Theory

The Love Spell Potential - The Big Bang Theory

Season 6 | Episode 23 Amy and Sheldon's relationship takes a surprising turn during a game of "Dungeons & Dragons"; Lucy and Koothrappali have an awkward date.

The Bon Voyage Reaction - The Big Bang Theory

The Bon Voyage Reaction - The Big Bang Theory

Season 6 | Episode 24 When Leonard receives an exciting opportunity to work overseas, Penny and Sheldon are thrown for a loop.

Season 7

The Hofstadter Insufficiency - The Big Bang Theory

The Hofstadter Insufficiency - The Big Bang Theory

Season 7 | Episode 1 With Leonard away, Sheldon and Penny spend quality time together sharing intimate secrets. Also, Wolowitz helps Raj get over his ex-girlfriend.

The Deception Verification - The Big Bang Theory

The Deception Verification - The Big Bang Theory

Season 7 | Episode 2 Leonard and Sheldon's friendship is tested; Wolowitz's relationship with his mom causes a threat to his masculinity.

The Scavenger Vortex - The Big Bang Theory

The Scavenger Vortex - The Big Bang Theory

Season 7 | Episode 3 When the entire gang competes in a scavenger hunt designed by Raj, it brings out the best - and worst - in everyone.

The Raiders Minimization - The Big Bang Theory

The Raiders Minimization - The Big Bang Theory

Season 7 | Episode 4 Beverly Hofstadter writes a psychology book about Leonard which Penny buys and reads. Sheldon wants to ruin something for Amy after she ruins an Indiana Jones movie for him. Raj and Stuart try online dating.

The Workplace Proximity - The Big Bang Theory

The Workplace Proximity - The Big Bang Theory

Season 7 | Episode 5 Amy starts working at Caltech which causes friction with Sheldon. Howard agrees with Sheldon who mentions this to Bernadette causing a big fight for the Wolowitzes.

The Romance Resonance - The Big Bang Theory

The Romance Resonance - The Big Bang Theory

Season 7 | Episode 6 Sheldon's latest scientific breakthrough leaves him feeling like a fraud; a romantic gesture between Howard and Bernadette causes Penny to up her game with Leonard.

The Proton Displacement - The Big Bang Theory

The Proton Displacement - The Big Bang Theory

Season 7 | Episode 7 When Professor Proton asks Leonard for help with an experiment, Sheldon retaliates by befriending Proton's rival, Bill Nye.

The Itchy Brain Simulation - The Big Bang Theory

The Itchy Brain Simulation - The Big Bang Theory

Season 7 | Episode 8 When a mistake comes to light, Sheldon makes Leonard walk a mile in his shoes; Penny decides to confront Raj's ex.

The Thanksgiving Decoupling - The Big Bang Theory

The Thanksgiving Decoupling - The Big Bang Theory

Season 7 | Episode 9 Sheldon protests when the gang drags him to Mrs. Wolowitz’s house for Thanksgiving. Meanwhile, Penny and Leonard must deal with a mistake from her past.

The Discovery Dissipation - The Big Bang Theory

The Discovery Dissipation - The Big Bang Theory

Season 7 | Episode 10 Leonard and Amy help Sheldon cope with the shame he’s feeling after his accidental contribution to science is disproved. Meanwhile, Raj must stay with Howard and Bernadette for a week.

The Cooper Extraction - The Big Bang Theory

The Cooper Extraction - The Big Bang Theory

Season 7 | Episode 11 While Sheldon is in Texas, the rest of the gang realizes how much he has changed their lives as they decorate the apartment Christmas tree.

The Hesitation Ramification - The Big Bang Theory

The Hesitation Ramification - The Big Bang Theory

Season 7 | Episode 12 When Penny’s big acting break on NCIS is a bust, Leonard struggles to help her, which results in Penny asking Leonard a bold relationship question. Meanwhile, Sheldon tries to learn how to be funny and Raj tries to work on his “game” before talking to girls.

The Occupation Recalibration - The Big Bang Theory

The Occupation Recalibration - The Big Bang Theory

Season 7 | Episode 13 Sheldon tries to relax after he is forced to take a vacation. Meanwhile, Leonard struggles to be supportive of Penny after she quits her job, and Bernadette seeks Stuart’s help in replacing one of Howard’s comic books.

The Convention Conundrum - The Big Bang Theory

The Convention Conundrum - The Big Bang Theory

Season 7 | Episode 14 After the guys can’t get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones. Meanwhile, the girls see if they can act like “grown-ups”.

The Locomotive Manipulation - The Big Bang Theory

The Locomotive Manipulation - The Big Bang Theory

Season 7 | Episode 15 Sheldon and Amy go on a trip to wine country with Howard and Bernadette; Penny and Leonard rush Raj's dog to the vet.

The Table Polarization - The Big Bang Theory

The Table Polarization - The Big Bang Theory

Season 7 | Episode 16 Leonard buys a dining room table and it causes Sheldon to reevaluate the changes in his life. Meanwhile, Wolowitz is offered a chance to go back to space and Bernadette struggles with whether or not to encourage him.

The Friendship Turbulence - The Big Bang Theory

The Friendship Turbulence - The Big Bang Theory

Season 7 | Episode 17 Bernadette tries to negotiate peace between Sheldon and Wolowitz; Penny receives an embarrassing offer; Raj wants Amy to write to a woman on his behalf.

The Mommy Observation - The Big Bang Theory

The Mommy Observation - The Big Bang Theory

Season 7 | Episode 18 When Sheldon visits his Mom in Houston, he is forced to confront a new reality. Meanwhile, Raj’s ‘Murder Mystery’ party starts some fights within the gang.

The Indecision Amalgamation - The Big Bang Theory

The Indecision Amalgamation - The Big Bang Theory

Season 7 | Episode 19 While Raj is wracked with guilt when he tries to date two women at once, Penny wrestles with whether to take a role in a cheesy movie and Sheldon is torn trying to choose between two gaming systems.

The Relationship Diremption - The Big Bang Theory

The Relationship Diremption - The Big Bang Theory

Season 7 | Episode 20 Sheldon faces a personal crisis after deciding he’s wasting his time with string theory. Meanwhile, a double date between Raj, Emily and the Wolowitzes ends in embarrassment for Howard.

The Anything Can Happen Recurrence - The Big Bang Theory

The Anything Can Happen Recurrence - The Big Bang Theory

Season 7 | Episode 21 To prepare for a date with Emily, Howard acclimates Raj to horror movies. Penny and Sheldon are upset when they discover Amy and Bernadette lied to avoid hanging out with them.

The Proton Transmogrification - The Big Bang Theory

The Proton Transmogrification - The Big Bang Theory

Season 7 | Episode 22 As the gang celebrates Star Wars Day, Sheldon discovers he is having difficulty dealing with the death of Professor Proton.

The Gorilla Dissolution - The Big Bang Theory

The Gorilla Dissolution - The Big Bang Theory

Season 7 | Episode 23 A bad day causes Penny to reevaluate her life choices – including Leonard. Meanwhile, Howard and Bernadette struggle to care for Mrs. Wolowitz, and Raj gets relationship advice from Sheldon.

The Status Quo Combustion - The Big Bang Theory

The Status Quo Combustion - The Big Bang Theory

Season 7 | Episode 24 Sheldon get upset about his career, the destruction of the comic book store and Leonard and Penny's future living arrangements. Howard and Bernadette can't keep hold of a carer for his mother. With his entire world changing around him, Sheldon considers a major move.

Season 8

The Locomotion Interruption - The Big Bang Theory

The Locomotion Interruption - The Big Bang Theory

Season 8 | Episode 1 Leonard and Amy make an unexpected trip to Arizona to fetch Sheldon; Penny interviews for a job at Bernadette's company; Stuart's relationship with Mrs. Wolowitz disturbs Howard.

The Junior Professor Solution - The Big Bang Theory

The Junior Professor Solution - The Big Bang Theory

Season 8 | Episode 2 When Sheldon must teach a class, Howard decides to take it. Amy takes advantage of the tension between Penny and Bernadette.

The First Pitch Insufficiency - The Big Bang Theory

The First Pitch Insufficiency - The Big Bang Theory

Season 8 | Episode 3 Wolowitz feels nervous when he is asked to throw the first pitch at a Los Angeles Angels game. Penny and Leonard want to prove Sheldon wrong after he says he and Amy are the better couple.

The Hook-Up Reverberation - The Big Bang Theory

The Hook-Up Reverberation - The Big Bang Theory

Season 8 | Episode 4 Raj's honesty comes back to haunt him when his new girlfriend is unfriendly to Penny. The guys think about becoming part owners in Stuart's store.

The Focus Attenuation - The Big Bang Theory

The Focus Attenuation - The Big Bang Theory

Season 8 | Episode 5 During their weekend in Las Vegas, Bernadette and Amy accuse Penny of being a buzz kill. The guys try to invent the next big thing.

The Expedition Approximation - The Big Bang Theory

The Expedition Approximation - The Big Bang Theory

Season 8 | Episode 6 Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel deep underground. Leonard and Penny seek advice from Howard and Bernadette after they fight about money.

The Misinterpretation Agitation - The Big Bang Theory

The Misinterpretation Agitation - The Big Bang Theory

Season 8 | Episode 7 The guys try to help Penny out of an awkward work dilemma, when a smitten doctor shows up at her door after her flirtatious sales techniques work a little too well. Meanwhile, Amy and Bernadette argue over whether or not female scientists should play up their sexuality.

The Prom Equivalency - The Big Bang Theory

The Prom Equivalency - The Big Bang Theory

Season 8 | Episode 8 When the gang recreates a high-school prom night on the roof of the guys'; apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

The Septum Deviation - The Big Bang Theory

The Septum Deviation - The Big Bang Theory

Season 8 | Episode 9 When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj's parents' impending divorce causes Howard and Bernadette to work on their own marriage.

The Champagne Reflection - The Big Bang Theory

The Champagne Reflection - The Big Bang Theory

Season 8 | Episode 10 While Sheldon says a tearful goodbye to the final installment of "Fun with Flags", Leonard, Howard and Raj search for something significant in a dead professor's research. And Bernadette is shocked to learn of her co-workers’ true feelings from Penny.

The Clean Room Infiltration - The Big Bang Theory

The Clean Room Infiltration - The Big Bang Theory

Season 8 | Episode 11 Leonard and Howard turn to Raj for help in dealing with a work emergency when they nearly come to blows after blaming each other for a potential disaster at the university. Amy throws an authentic Victorian Christmas party, while Sheldon seeks revenge on her for making him celebrate the holidays.

The Space Probe Disintegration - The Big Bang Theory

The Space Probe Disintegration - The Big Bang Theory

Season 8 | Episode 12 Wolowitz tries to distract Raj, who is anxiously awaiting data from a space probe he helped launch. Meanwhile, Sheldon and Leonard go dress shopping with Penny and Amy.

The Anxiety Optimization - The Big Bang Theory

The Anxiety Optimization - The Big Bang Theory

Season 8 | Episode 13 The gang tries to help Sheldon when he becomes stuck in a rut at work by increasing his anxiety level. Howard teases Raj with a new game called "Cinnamon or Emily?"

The Troll Manifestation - The Big Bang Theory

The Troll Manifestation - The Big Bang Theory

Season 8 | Episode 14 Leonard and Sheldon publish a paper which is widely accepted except for comments from an internet troll. Meanwhile, the girls reminisce about embarrassing incidents from their past.

The Comic Book Store Regeneration - The Big Bang Theory

The Comic Book Store Regeneration - The Big Bang Theory

Season 8 | Episode 15 Wolowitz receives some shocking news as everyone prepares for the reopening of Stuart’s comic book store. Penny teaches Sheldon how to “let it go,” but can’t follow her own advice after she learns something infuriating about Amy. Also, Leonard and Raj think they spot Nathan Fillion at a restaurant.

The Intimacy Acceleration - The Big Bang Theory

The Intimacy Acceleration - The Big Bang Theory

Season 8 | Episode 16 As a joke, Sheldon and Penny try an experiment designed to make participants fall in love. Also, Leonard, Amy, Raj and Emily spend the evening trying to escape a room with a “zombie.” And, after returning from Mrs. Wolowitz’ funeral, Bernadette and Howard run into trouble at the airport.

The Colonization Application - The Big Bang Theory

The Colonization Application - The Big Bang Theory

Season 8 | Episode 17 Trouble arises when Amy learns Sheldon has applied for a one-way mission to colonize Mars. Also, a trip to the pet store ends in a fight for Sheldon and Amy, Leonard surprises Penny with a very “adult” purchase, and Raj is caught snooping in Emily’s apartment.

The Leftover Thermalization - The Big Bang Theory

The Leftover Thermalization - The Big Bang Theory

Season 8 | Episode 18 Friction ensues when a magazine fails to mention Leonard in an article about the paper he co-wrote with Sheldon. Also, a blackout at Mrs. Wolowitz’s home leads to a final family dinner in her honor.

The Skywalker Incursion - The Big Bang Theory

The Skywalker Incursion - The Big Bang Theory

Season 8 | Episode 19 When Leonard and Sheldon are invited to speak at UC Berkeley, they take a detour to try to meet an idol. Also, when Bernadette and Howard battle over the fate of his Doctor Who TARDIS, Raj and Amy offer to settle the dispute with a game of ping pong.

The Fortification Implementation - The Big Bang Theory

The Fortification Implementation - The Big Bang Theory

Season 8 | Episode 20 When Sheldon and Amy build a blanket fort, they come to major crossroads in their relationship. Also, Wolowitz meets the half-brother he never knew he had, and when Penny is invited to appear on Wil Wheaton’s podcast, she and Leonard have a huge, on-air argument.

The Communication Deterioration - The Big Bang Theory

The Communication Deterioration - The Big Bang Theory

Season 8 | Episode 21 When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Also, Penny is torn between auditioning for a movie or keeping her successful pharmaceutical sales job.

The Graduation Transmission - The Big Bang Theory

The Graduation Transmission - The Big Bang Theory

Season 8 | Episode 22 Wolowitz questions his engineering abilities when he and Sheldon can’t get a toy drone to fly. Meanwhile, a cancelled flight nearly prevents Leonard from giving the commencement address at his former high school, and Raj pits his parents against each other when his father cuts him off financially.

The Maternal Combustion - The Big Bang Theory

The Maternal Combustion - The Big Bang Theory

Season 8 | Episode 23 Personalities collide when Sheldon and Leonard’s mothers finally meet. Meanwhile, Howard finally decides to “man up” and do his fair share of the housework – but not without a little help from his friends.

The Commitment Determination - The Big Bang Theory

The Commitment Determination - The Big Bang Theory

Season 8 | Episode 24 Sheldon pushes Leonard and Penny to choose a date for their wedding and deals with dramatic changes in his own relationship with Amy.

Season 9

The Matrimonial Momentum - The Big Bang Theory

The Matrimonial Momentum - The Big Bang Theory

Season 9 | Episode 1 After driving to Vegas to get married, Penny struggles with Leonard’s confession that he kissed another girl. Also, Sheldon doesn't know how to act after Amy pushes pause on their relationship.

The Separation Oscillation - The Big Bang Theory

The Separation Oscillation - The Big Bang Theory

Season 9 | Episode 2 Leonard confronts the woman he kissed on the North Sea in an attempt to set Penny's mind at ease. Also, Sheldon films a special episode of "Fun with Flags" after his breakup with Amy, and Bernadette feels guilty about withholding a secret from Penny.

The Bachelor Party Corrosion - The Big Bang Theory

The Bachelor Party Corrosion - The Big Bang Theory

Season 9 | Episode 3 The guys' science skills are put to the test when they get a flat tire during Leonard's bachelor party weekend in Mexico. Also, the girls force Penny to finally tell her family that she eloped with Leonard.

The 2003 Approximation - The Big Bang Theory

The 2003 Approximation - The Big Bang Theory

Season 9 | Episode 4 Sheldon learns of an impending change in his living arrangements and decides to revert back to 2003, a simpler time before he met Leonard and Penny. Also, Howard and Raj form a band to play at the Comic Book Store.

The Perspiration Implementation - The Big Bang Theory

The Perspiration Implementation - The Big Bang Theory

Season 9 | Episode 5 The guys take a fencing lesson from Barry Kripke and Sheldon finds himself in an awkward position when Kripke expresses interest in Amy. Also, when Stuart struggles to get female customers at the Comic Book Store, Penny, Amy and Bernadette come by to help him out.

The Helium Insufficiency - The Big Bang Theory

The Helium Insufficiency - The Big Bang Theory

Season 9 | Episode 6 In the midst of a nation-wide helium shortage, Sheldon and Leonard take desperate measures to get the supplies they need. Also, Penny and Bernadette download a dating app on Amy's phone to try and find her a new man.

The Spock Resonance - The Big Bang Theory

The Spock Resonance - The Big Bang Theory

Season 9 | Episode 7 Wil Wheaton interviews Sheldon for a Star Trek documentary where he reveals the ring and his plan to propose to Amy. Bernadette wants to start renovating the house and the topic of starting a family together with Howard is brought up.

The Mystery Date Observation - The Big Bang Theory

The Mystery Date Observation - The Big Bang Theory

Season 9 | Episode 8 Sheldon, Wolowitz and Koothrappali post an online advertisement to find Sheldon a new girlfriend. Also, when Amy is coy with details about a guy she is dating, Penny and Bernadette decide to spy

The Platonic Permutation - The Big Bang Theory

The Platonic Permutation - The Big Bang Theory

Season 9 | Episode 9 Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily, and Penny discovers that Leonard knows more about her than she thought.

The Earworm Reverberation - The Big Bang Theory

The Earworm Reverberation - The Big Bang Theory

Season 9 | Episode 10 Sheldon has a revelation when he realizes why a song was stuck in his head. Also, Amy invites Dave over for dinner despite their previously awkward date, and Wolowitz and Koothrappali become obsessed with a fan of their band, "Footprints on the Moon".

The Opening Night Excitation - The Big Bang Theory

The Opening Night Excitation - The Big Bang Theory

Season 9 | Episode 11 After more than five years of dating, Sheldon and Amy spend their first night together. Also, Leonard, Wolowitz, and Koothrappali must decide who will take their extra Star Wars movie ticket.

The Sales Call Sublimation - The Big Bang Theory

The Sales Call Sublimation - The Big Bang Theory

Season 9 | Episode 12 Penny gets more than she bargained for when Leonard agrees to meet with a psychiatrist on her behalf. Also, Sheldon and Koothrappali collaborate on an astronomical discovery, and Wolowitz and Bernadette can't believe what they are feeling after Stuart moves out.

The Empathy Optimization - The Big Bang Theory

The Empathy Optimization - The Big Bang Theory

Season 9 | Episode 13 After having to deal with a sick Sheldon, Leonard, Penny and the gang try to treat themselves to a Sheldon-free weekend.

The Meemaw Materialization - The Big Bang Theory

The Meemaw Materialization - The Big Bang Theory

Season 9 | Episode 14 Meemaw meets Amy, but it isn't all roses. Meemaw seems to have an axe to grind with her. Sheldon comes to Amy's defense, but not before Meemaw lets a little secret of his slip.

The Valentino Submergence - The Big Bang Theory

The Valentino Submergence - The Big Bang Theory

Season 9 | Episode 15 Sheldon and Amy host a live Valentine's Day episode of Fun with Flags, Leonard and Penny grapple with getting older, Howard and Bernadette find a surprise in their hot tub and Raj is torn between Emily and the cute girl he met at the Comic Bookstore.

The Positive Negative Reaction - The Big Bang Theory

The Positive Negative Reaction - The Big Bang Theory

Season 9 | Episode 16 When the gang finds out about Bernadette’s pregnancy, they celebrate by singing karaoke. Also, Bernadette is concerned when Wolowitz freaks out over her pregnancy announcement, and Wolowitz is convinced he must make more money to provide for the baby.

The Celebration Experimentation - The Big Bang Theory

The Celebration Experimentation - The Big Bang Theory

Season 9 | Episode 17 After more than nine years together, the gang finally celebrates Sheldon’s birthday, surprising him with a special guest.

The Application Deterioration - The Big Bang Theory

The Application Deterioration - The Big Bang Theory

Season 9 | Episode 18 Leonard, Sheldon, and Wolowitz run into problems when they file for a patent for their infinite persistence gyroscope. Also, Penny, Amy and Bernadette give Koothrappali dating advice when Emily reaches out to him after their breakup.

The Solder Excursion Diversion - The Big Bang Theory

The Solder Excursion Diversion - The Big Bang Theory

Season 9 | Episode 19 Amy is shocked at a revelation from Sheldon after she buys him a new laptop. Also, Koothrappali sells out Leonard and Wolowitz after they lie to their wives in order to attend an early screening of a movie.

The Big Bear Precipitation - The Big Bang Theory

The Big Bear Precipitation - The Big Bang Theory

Season 9 | Episode 20 Sheldon spills a secret of Leonard’s when the two take a weekend cabin trip with Penny and Amy. Also, when Koothrappali goes overboard with pregnancy gifts, Wolowitz and Bernadette must draw the line.

The Viewing Party Combustion - The Big Bang Theory

The Viewing Party Combustion - The Big Bang Theory

Season 9 | Episode 21 Everyone must choose sides when a small argument between Leonard and Sheldon erupts into a heated fight during a group get-together.

The Fermentation Bifurcation - The Big Bang Theory

The Fermentation Bifurcation - The Big Bang Theory

Season 9 | Episode 22 The gang goes to a wine bar and runs into Penny’s old boyfriend, Zack. Also, Bernadette gets stuck spending the evening with Sheldon when she can’t go wine tasting with the group, and things don’t go as planned when Koothrappali introduces his new girlfriend, Claire.

The Line Substitution Solution - The Big Bang Theory

The Line Substitution Solution - The Big Bang Theory

Season 9 | Episode 23 Sheldon hires Stuart to spend the day with Amy when he’d rather go to a movie screening. Also, Leonard’s mother, Beverly, comes to town and Penny struggles to make a connection with her.

The Convergence Convergence - The Big Bang Theory

The Convergence Convergence - The Big Bang Theory

Season 9 | Episode 24 Chaos ensues when Leonard’s recently divorced parents, Alfred and Beverly, and Sheldon’s devoutly religious mother, Mary, come to town. Also, Wolowitz and Koothrappali think the government is out to get them when they are contacted about their guidance system.

Season 10

The Conjugal Conjecture - The Big Bang Theory

The Conjugal Conjecture - The Big Bang Theory

Season 10 | Episode 1 After Sheldon’s mother and Leonard's father share an evening together, everyone deals with an awkward morning the next day. Also, Penny’s family arrives for the wedding ceremony, including her anxiety-ridden mother, Susan, and her drug dealing brother, Randall.

The Military Miniaturization - The Big Bang Theory

The Military Miniaturization - The Big Bang Theory

Season 10 | Episode 2 Colonel Williams, an Air Force representative from the Department of Material Command sits down to talk with Wolowitz.

The Dependence Transcendence - The Big Bang Theory

The Dependence Transcendence - The Big Bang Theory

Season 10 | Episode 3 Tensions rise when the boys struggle to complete their government project on time and Sheldon tries an energy drink to stay awake. Also, Penny and Amy go to a “party” at Bert the geologist’s house, and Koothrappali learns Bernadette’s true feelings about her pregnancy when they clean out the future baby room.

The Cohabitation Experimentation - The Big Bang Theory

The Cohabitation Experimentation - The Big Bang Theory

Season 10 | Episode 4 When Amy’s apartment floods, she proposes a “cohabitation experiment” with Sheldon. Also, Howard and Bernadette are upset when Koothrappali learns the gender of the baby before they do.

The Hot Tub Contamination - The Big Bang Theory

The Hot Tub Contamination - The Big Bang Theory

Season 10 | Episode 5 Leonard and Penny must separate a quarreling Sheldon and Amy when their cohabitation does not go as planned, and Sheldon threatens to break off their relationship when Amy refuses to adhere to the bathroom schedule. Also, Howard and Bernadette find unexpected guests at their house when they decide to stay home from a planned vacation.

The Fetal Kick Catalyst - The Big Bang Theory

The Fetal Kick Catalyst - The Big Bang Theory

Season 10 | Episode 6 Penny is surprised to learn she has fans of her performance in "Serial Ape-ist" when she attends Van Nuys Comic Con with Leonard. Also, Amy hosts a Sheldon-style brunch at Penny’s apartment, and Wolowitz makes an impulsive purchase when he starts stressing out about the baby on the way.

The Veracity Elasticity - The Big Bang Theory

The Veracity Elasticity - The Big Bang Theory

Season 10 | Episode 7 In order to continue living with Sheldon, Amy lies to him about repairs being made to her apartment and they host an "on location" episode of "Fun With Flags" in Penny’s apartment. Also, Leonard lets Penny decorate Sheldon’s old room after he learns that she has been secretly moving Leonard’s collectibles into storage.

The Brain Bowl Incubation - The Big Bang Theory

The Brain Bowl Incubation - The Big Bang Theory

Season 10 | Episode 8 After a successful experiment combining their genes, Sheldon will stop at nothing to convince Amy they should procreate. Also, Koothrappali is embarrassed to tell the gang what the new woman he’s dating does for a living.

The Geology Elevation - The Big Bang Theory

The Geology Elevation - The Big Bang Theory

Season 10 | Episode 9 When Bert, a Caltech geologist, wins the MacArthur Genius fellowship, Sheldon is overcome with jealousy. Also, Wolowitz finds an old remote control Stephen Hawking action figure he invented.

The Property Division Collision - The Big Bang Theory

The Property Division Collision - The Big Bang Theory

Season 10 | Episode 10 Sheldon and Leonard try to divvy up their shared belongings, but can’t agree on anything. Also, Koothrappali and Stuart fight to be the most helpful during Bernadette’s final weeks of pregnancy.

The Birthday Synchronicity - The Big Bang Theory

The Birthday Synchronicity - The Big Bang Theory

Season 10 | Episode 11 Howard and Bernadette welcome their new baby and Sheldon and Amy celebrate Amy’s birthday.

The Holiday Summation - The Big Bang Theory

The Holiday Summation - The Big Bang Theory

Season 10 | Episode 12 Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas.

The Romance Recalibration - The Big Bang Theory

The Romance Recalibration - The Big Bang Theory

Season 10 | Episode 13 When Penny feels that Leonard is taking her for granted, she decides to go on a spa weekend with Amy. Also, Wolowitz and Koothrappali try to fix a squeaky floorboard in the baby’s room.

The Emotion Detection Automation - The Big Bang Theory

The Emotion Detection Automation - The Big Bang Theory

Season 10 | Episode 14 Sheldon beta-tests an MIT invention after hearing it can help him read people’s emotions. Also, Leonard can’t hide his feelings when Penny announces her brother is coming to town, and Raj invites his ex-girlfriends over to give him dating advice.

The Locomotion Reverberation - The Big Bang Theory

The Locomotion Reverberation - The Big Bang Theory

Season 10 | Episode 15 Leonard and Wolowitz try to distract Sheldon when he slows the progress of their guidance system. Also, Penny and Amy take Bernadette out for the night, leaving Raj and Stuart to care for baby Halley.

The Allowance Evaporation - The Big Bang Theory

The Allowance Evaporation - The Big Bang Theory

Season 10 | Episode 16 Sheldon and Amy have their first fight since moving in together, and Koothrappali is shocked at the realities of financial independence when he stops receiving support from his father.

The Comic-Con Conundrum - The Big Bang Theory

The Comic-Con Conundrum - The Big Bang Theory

Season 10 | Episode 17 With Koothrappali cut off from his father’s fortune, he appoints Sheldon to help him get out of debt. Also, Penny considers joining Leonard at Comic-Con.

The Escape Hatch Identification - The Big Bang Theory

The Escape Hatch Identification - The Big Bang Theory

Season 10 | Episode 18 When Raj moves out of his apartment, Leonard and Penny offer him Sheldon's old room.

The Collaboration Fluctuation - The Big Bang Theory

The Collaboration Fluctuation - The Big Bang Theory

Season 10 | Episode 19 Leonard, Penny and Raj adjust to their new living arrangement, and Sheldon takes an interest in Amy’s work.

The Recollection Dissipation - The Big Bang Theory

The Recollection Dissipation - The Big Bang Theory

Season 10 | Episode 20 Sheldon pushes himself to the limit when he collaborates on projects with Leonard and Wolowitz as well as Amy on the same day. Also, Bernadette is nearing the end of her maternity leave and must return to work.

The Separation Agitation - The Big Bang Theory

The Separation Agitation - The Big Bang Theory

Season 10 | Episode 21 Howard and Bernadette have a hard time leaving Halley in day care when Bernadette returns to work. Also, Bert introduces the gang to his new girlfriend, Rebecca.

The Cognition Regeneration - The Big Bang Theory

The Cognition Regeneration - The Big Bang Theory

Season 10 | Episode 22 Leonard isn’t thrilled when Penny considers taking a new job offered by her ex-boyfriend, Zack.

The Gyroscopic Collapse - The Big Bang Theory

The Gyroscopic Collapse - The Big Bang Theory

Season 10 | Episode 23 After Leonard, Sheldon and Wolowitz celebrate the completion of the top secret air force project, they are met with an unpleasant surprise. Also, Amy is offered a summer position as a visiting researcher.

The Long Distance Dissonance - The Big Bang Theory

The Long Distance Dissonance - The Big Bang Theory

Season 10 | Episode 24 The gang is concerned when Sheldon’s former admirer, Dr. Ramona Nowitzki, resurfaces while Amy is away at Princeton.

Season 11

The Proposal Proposal - The Big Bang Theory

The Proposal Proposal - The Big Bang Theory

Season 11 | Episode 1 In the eleventh season opener, Amy gives Sheldon an answer to his proposal while Howard and Bernadette struggle with some unexpected news.

The Retraction Reaction - The Big Bang Theory

The Retraction Reaction - The Big Bang Theory

Season 11 | Episode 2 Leonard angers the university – and the entire physics community – after he gives an embarrassing interview. Also, Amy and Bernadette bond over having to hide their success from Sheldon and Howard.

The Relaxation Integration - The Big Bang Theory

The Relaxation Integration - The Big Bang Theory

Season 11 | Episode 3 Sheldon struggles with picking a wedding date. Amy decides she wants a wedding near a cliff which Sheldon doesn't want. Meanwhile Raj and Stuart fight over one of Bernadette's co-workers.

The Explosion Implosion - The Big Bang Theory

The Explosion Implosion - The Big Bang Theory

Season 11 | Episode 4 As Howard worries about fatherhood, he and Sheldon bond when they jointly assemble a model rocket. Meanwhile, Penny bonds with Leonard's mother, Beverly, much to his concern.

The Collaboration Contamination - The Big Bang Theory

The Collaboration Contamination - The Big Bang Theory

Season 11 | Episode 5 Sheldon and Koothrappali confide in Bernadette when they can't handle Amy and Wolowitz working together. Also, Penny and Leonard learn new tactics for how to deal Sheldon from an unlikely source.

The Proton Regeneration - The Big Bang Theory

The Proton Regeneration - The Big Bang Theory

Season 11 | Episode 6 Sheldon goes head-to-head with Wil Wheaton for the role of the new Professor Proton. Also, Penny steps in to take care of Halley when Bernadette and Wolowitz both wind up on bed rest.

The Geology Methodology - The Big Bang Theory

The Geology Methodology - The Big Bang Theory

Season 11 | Episode 7 Sheldon and Bert collaborate on a research project, despite Sheldon’s embarrassment. Also, Penny and Bernadette coach Koothrappali on how to navigate his relationship with Ruchi.

The Tesla Recoil - The Big Bang Theory

The Tesla Recoil - The Big Bang Theory

Season 11 | Episode 8 Leonard and Wolowitz are furious after they learn Sheldon went to work with the military behind their backs. Also, while Bernadette is on bed rest, she asks Raj to do some digging when she suspects Ruchi is trying to steal her job.

The Bitcoin Entanglement - The Big Bang Theory

The Bitcoin Entanglement - The Big Bang Theory

Season 11 | Episode 9 Sheldon tries to teach the guys a lesson after they cut him out of a potentially valuable Bitcoin investment. Also, a seven-year-old video reveals a secret about Leonard and Penny's relationship.

The Confidence Erosion - The Big Bang Theory

The Confidence Erosion - The Big Bang Theory

Season 11 | Episode 10 Sheldon and Amy try to eliminate stress from wedding planning by applying math to the process. Also, Koothrappali “breaks up” with Wolowitz after realizing his best friend is actually hurting his confidence.

The Celebration Reverberation - The Big Bang Theory

The Celebration Reverberation - The Big Bang Theory

Season 11 | Episode 11 Sheldon and Wolowitz plan birthday celebrations for Amy and Halley, respectively. Also, Leonard get a Christmas letter from his brother that causes him to spiral out about his own lack of accomplishments.

The Matrimonial Metric - The Big Bang Theory

The Matrimonial Metric - The Big Bang Theory

Season 11 | Episode 12 Sheldon and Amy will try to use science to see who should be their Maid of Honor and Best Man.

The Solo Oscillation - The Big Bang Theory

The Solo Oscillation - The Big Bang Theory

Season 11 | Episode 13 When Sheldon kicks Amy out to work solo, she and Leonard bond during a series of science experiments. Also, Bert the geologist replaces Wolowitz in the band Footprints on the Moon, and Sheldon finds Penny a surprising source of scientific inspiration.

The Separation Triangulation - The Big Bang Theory

The Separation Triangulation - The Big Bang Theory

Season 11 | Episode 14 Koothrappali finds himself in the middle of domestic drama when he learns the woman he's dating, has a very upset husband. Also, when Sheldon rents his old room back for a quiet place to work, he drives Leonard crazy by being a model tenant.

The Novelization Correlation - The Big Bang Theory

The Novelization Correlation - The Big Bang Theory

Season 11 | Episode 15 Leonard's book raises questions, and Amy guest stars on the new Professor Proton show.

The Neonatal Nomenclature - The Big Bang Theory

The Neonatal Nomenclature - The Big Bang Theory

Season 11 | Episode 16 When Bernadette won't go into labor, the gang tries different tactics to get things started. Howard confronts Bernadette after Amy accidentally reveals she's already chosen their son's name.

The Athenaeum Allocation - The Big Bang Theory

The Athenaeum Allocation - The Big Bang Theory

Season 11 | Episode 17 Leonard jumps through hoops to help secure the perfect wedding venue for Sheldon and Amy. Also, Bernadette and Wolowitz have a hard time deciding who should stay at home with the kids and who should go back to work.

The Gates Excitation - The Big Bang Theory

The Gates Excitation - The Big Bang Theory

Season 11 | Episode 18 Bill Gates visits Penny's work, and the gang schemes to meet him. Hilarity ensues.

The Tenant Disassociation - The Big Bang Theory

The Tenant Disassociation - The Big Bang Theory

Season 11 | Episode 19 When Leonard learns Sheldon is the president of the tenants association, he decides to run against him. Also, Bernadette encourages Wolowitz and Koothrappali to find the owner of a drone after they find it in the backyard.

The Reclusive Potential - The Big Bang Theory

The Reclusive Potential - The Big Bang Theory

Season 11 | Episode 20 A brilliant but reclusive scientist, Doctor Wolcott, invites Sheldon to his cabin in the middle of nowhere, and Leonard, Raj and Howard go along for the trip. Also, Penny and Bernadette improvise after Amy doesn’t like the tame bachelorette party they planned for her.

The Comet Polarization - The Big Bang Theory

The Comet Polarization - The Big Bang Theory

Season 11 | Episode 21 Sheldon’s comic book store experiences changes when writer Neil Gaiman puts Stuart’s store on the map. Also, Koothrappali takes credit for Penny’s astronomical discovery, and friendships are threatened.

The Monetary Insufficiency - The Big Bang Theory

The Monetary Insufficiency - The Big Bang Theory

Season 11 | Episode 22 Sheldon goes to Vegas to win money for science. Also, Penny and Bernadette take Amy wedding dress shopping, but her terrible choice entangles them in a web of lies.

The Sibling Realignment - The Big Bang Theory

The Sibling Realignment - The Big Bang Theory

Season 11 | Episode 23 When Sheldon learns that his mother won’t attend his wedding unless he invites his brother, Georgie, he and Leonard travel to Texas to end a family feud. Also, the Wolowitz kids inadvertently infest Amy, Bernadette, Wolowitz and Koothrappali with pinkeye.

The Bow Tie Asymmetry - The Big Bang Theory

The Bow Tie Asymmetry - The Big Bang Theory

Season 11 | Episode 24 When Amy's parents and Sheldon's family arrive, everybody is focused to make sure all wedding arrangements go according to plan – everyone except the bride and groom.