The Bat Jar Conjecture: Sheldon is ousted from the gang's Physics Bowl quiz team, so he decides to prove his superiority by forming his own team for the event. (S1 Ep13) [AD,S]
The Bat Jar Conjecture: Sheldon is ousted from the gang's Physics Bowl quiz team, so he decides to prove his superiority by forming his own team for the event. (S1 Ep13) [AD,S]
The Birthday Synchronicity: Sheldon and Amy try to celebrate her birthday with an intimate night at home but are interrupted when Bernadette goes into labour. (S10 Ep11) [AD,S]
The Holiday Summation: After spending Christmas apart, the gang gather at Penny and Leonard's flat and hear about Sheldon and Amy's terrible trip to Texas. (S10 Ep12) [AD,S]
The Romance Recalibration: Penny thinks that Leonard has stopped making an effort in their relationship, so she decides to go away for a spa weekend with Amy. (S10 Ep13) [AD,S]
The Emotion Detection Automation: Sheldon tests a new invention after hearing that it could help him to read people's emotions. Raj seeks dating advice. (S10 Ep14) [AD,S]
The Nerdvana Annihilation: When Penny makes fun of Leonard's habit of collecting goofy memorabilia, his friends kick up a fuss and try to keep him on the side of the nerds. (S1 Ep14) [AD,S]
The Shiksa Indeterminacy: Leonard, Raj and Howard all fall heavily for Sheldon's twin sister, but when Leonard comes up with a plan to win her heart, it's derailed by Sheldon. (S1 Ep15) [AD,S]
The Nerdvana Annihilation: When Penny makes fun of Leonard's habit of collecting goofy memorabilia, his friends kick up a fuss and try to keep him on the side of the nerds. (S1 Ep14) [AD,S]
The Shiksa Indeterminacy: Leonard, Raj and Howard all fall heavily for Sheldon's twin sister, but when Leonard comes up with a plan to win her heart, it's derailed by Sheldon. (S1 Ep15) [AD,S]
The Matrimonial Momentum: Penny struggles with Leonard's confession that he kissed another woman. Sheldon doesn't know how to act when Amy breaks up with him. (S9 Ep1) [AD,S]
The Separation Oscillation: Sheldon films a special post-break-up episode of Fun with Flags. Bernadette feels guilty about withholding a secret from Penny. (S9 Ep2) [AD,S]
The Matrimonial Momentum: Penny struggles with Leonard's confession that he kissed another woman. Sheldon doesn't know how to act when Amy breaks up with him. (S9 Ep1) [AD,S]
The Separation Oscillation: Sheldon films a special post-break-up episode of Fun with Flags. Bernadette feels guilty about withholding a secret from Penny. (S9 Ep2) [AD,S]
The Decision Reverberation: Raj publishes a paper that suggests he may have discovered alien life. Penny encourages Leonard to stand up for himself. (S12 Ep20) [AD,S]
The Plagiarism Schism: Barry Kripke finds proof that Dr Pemberton plagiarised his thesis in college. Should Sheldon and Amy turn in their rival? (S12 Ep21) [AD,S]
The Maternal Conclusion: Leonard is surprised when his mother Beverly comes to visit and is kind to him, until he finds out the real reason she's there. (S12 Ep22) [AD,S]
The Decision Reverberation: Raj publishes a paper that suggests he may have discovered alien life. Penny encourages Leonard to stand up for himself. (S12 Ep20) [AD,S]
The Change Constant: Sheldon and Amy stay up late awaiting a phone call that could bring big news from the Nobel Committee: are their lives about to change? (S12 Ep23) [AD,S]
The Plagiarism Schism: Barry Kripke finds proof that Dr Pemberton plagiarised his thesis in college. Should Sheldon and Amy turn in their rival? (S12 Ep21) [AD,S]
The Maternal Conclusion: Leonard is surprised when his mother Beverly comes to visit and is kind to him, until he finds out the real reason she's there. (S12 Ep22) [AD,S]
The Change Constant: Sheldon and Amy stay up late awaiting a phone call that could bring big news from the Nobel Committee: are their lives about to change? (S12 Ep23) [AD,S]
The Peanut Reaction: Penny throws a surprise party for Leonard, with help from Howard and Raj, but Sheldon's indulgence in an electronics shop throws her off track. (S1 Ep16) [AD,S]
The Tangerine Factor: When Penny breaks up with her boyfriend, Leonard plucks up the courage to ask her out. And each of them turns to Sheldon for advice about their date. (S1 Ep17) [AD,S]
The Peanut Reaction: Penny throws a surprise party for Leonard, with help from Howard and Raj, but Sheldon's indulgence in an electronics shop throws her off track. (S1 Ep16) [AD,S]
The Tangerine Factor: When Penny breaks up with her boyfriend, Leonard plucks up the courage to ask her out. And each of them turns to Sheldon for advice about their date. (S1 Ep17) [AD,S]
The Locomotion Reverberation: Leonard and Howard distract Sheldon with a trip to a historic railway when he slows their progress on the guidance system. (S10 Ep15) [AD,S]
The Allowance Evaporation: Amy is furious when she learns that Sheldon has shared intimate details of their relationship with his colleagues. (S10 Ep16) [AD,S]
The Comic-Con Conundrum: Cut off from his father's fortune, Raj appoints Sheldon to organise his finances. Penny considers joining the guys at Comic-Con. (S10 Ep17) [AD,S]
The Escape Hatch Identification: Leonard and Penny offer Sheldon's old room to Raj when he's forced to move out of his flat, leading to unexpected conflict. (S10 Ep18) [AD,S]
The Bad Fish Paradigm: Penny opens up to a reluctant Sheldon after a less-than-stellar first date with Leonard, putting him in the awkward position of having to keep a secret. (S2 Ep1) [AD,S]
The Codpiece Topology: Seeing Penny out on a date with another guy sends a distressed Leonard rushing back to Leslie Winkle, much to Sheldon's dismay. (S2 Ep2) [AD,S]
The Bad Fish Paradigm: Penny opens up to a reluctant Sheldon after a less-than-stellar first date with Leonard, putting him in the awkward position of having to keep a secret. (S2 Ep1) [AD,S]
The Codpiece Topology: Seeing Penny out on a date with another guy sends a distressed Leonard rushing back to Leslie Winkle, much to Sheldon's dismay. (S2 Ep2) [AD,S]
The Bachelor Party Corrosion: The guys' science skills are tested when they get a flat tyre during Leonard's surprise bachelor party weekend in Mexico. (S9 Ep3) [AD,S]
The 2003 Approximation: Sheldon sulks when Penny and Leonard announce that they're moving in together. Howard and Raj form a band to play at the comic book shop. (S9 Ep4) [AD,S]
The Bachelor Party Corrosion: The guys' science skills are tested when they get a flat tyre during Leonard's surprise bachelor party weekend in Mexico. (S9 Ep3) [AD,S]
The 2003 Approximation: Sheldon sulks when Penny and Leonard announce that they're moving in together. Howard and Raj form a band to play at the comic book shop. (S9 Ep4) [AD,S]
The Stockholm Syndrome: Howard and Bernadette go on a trip without their children, Leonard and Penny try to keep a secret, and Raj makes a new friend. (S12 Ep24) [AD,S]
Pilot: The first ever episode of the hit sitcom. Leonard and Sheldon's geeky world is shaken up by the arrival of a beautiful new neighbour. (S1 Ep1) [AD,S]
The Stockholm Syndrome: Howard and Bernadette go on a trip without their children, Leonard and Penny try to keep a secret, and Raj makes a new friend. (S12 Ep24) [AD,S]
The Fuzzyboots Corollary: Leonard is upset when he discovers that Penny is seeing someone, so he plucks up the courage to ask a woman out on a date. (S1 Ep3) [AD,S]
Pilot: The first ever episode of the hit sitcom. Leonard and Sheldon's geeky world is shaken up by the arrival of a beautiful new neighbour. (S1 Ep1) [AD,S]
The Fuzzyboots Corollary: Leonard is upset when he discovers that Penny is seeing someone, so he plucks up the courage to ask a woman out on a date. (S1 Ep3) [AD,S]
The Barbarian Sublimation: Penny becomes addicted to an online game based on the world of Conan the Barbarian and begins to pester Sheldon for advice. (S2 Ep3) [AD,S]
The Griffin Equivalency: Full of confidence after being named one of People magazine's '30 to Watch Under 30', Raj hits on Penny and becomes impossibly arrogant. (S2 Ep4) [AD,S]
The Barbarian Sublimation: Penny becomes addicted to an online game based on the world of Conan the Barbarian and begins to pester Sheldon for advice. (S2 Ep3) [AD,S]
The Griffin Equivalency: Full of confidence after being named one of People magazine's '30 to Watch Under 30', Raj hits on Penny and becomes impossibly arrogant. (S2 Ep4) [AD,S]
The Collaboration Fluctuation: Leonard, Penny and Raj settle into their new living arrangement, and Sheldon expresses an interest in Amy's professional life. (S10 Ep19) [AD,S]
The Recollection Dissipation: Sheldon collaborates on two projects - one with Leonard and Howard, plus another with Amy - pushing himself to the limit. (S10 Ep20) [AD,S]
The Proposal Proposal: Amy must decide whether or not to marry Sheldon and gives him an answer to his proposal. Howard and Bernadette struggle with some unexpected news. (S11 Ep1) [AD,S]
The Retraction Reaction: Leonard angers the university during an embarrassing interview. Amy and Bernadette must hide their success from Sheldon and Howard. (S11 Ep2) [AD,S]
The Euclid Alternative: When Leonard can't drive Sheldon to and from work, the friends stage an intervention to overcome Sheldon's fear of getting behind the wheel. (S2 Ep5) [AD,S]
The Cooper-Nowitzki Theorem: Sheldon's friends are mystified when a younger student is attracted to him, and her intense devotion soon becomes too much to bear. (S2 Ep6) [AD,S]
The Euclid Alternative: When Leonard can't drive Sheldon to and from work, the friends stage an intervention to overcome Sheldon's fear of getting behind the wheel. (S2 Ep5) [AD,S]
The Cooper-Nowitzki Theorem: Sheldon's friends are mystified when a younger student is attracted to him, and her intense devotion soon becomes too much to bear. (S2 Ep6) [AD,S]
The Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [AD,S]
The Helium Insufficiency: Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app for Amy. (S9 Ep6) [AD,S]
The Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [AD,S]
The Helium Insufficiency: Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app for Amy. (S9 Ep6) [AD,S]
The Luminous Fish Effect: Getting fired forces Sheldon to ponder life outside physics, so Leonard has to take drastic action to snap his friend out of his reverie. (S1 Ep4) [AD,S]
The Hamburger Postulate: Leonard thinks he's been wasting his time on Penny, so he turns his attention to Leslie. Sheldon's uncomfortable with a change to his hamburger routine. (S1 Ep5) [AD,S]
The Middle Earth Paradigm: Penny's Halloween party puts Leonard, Sheldon, Howard and Raj through a demanding new test of their social skills. (S1 Ep6) [AD,S]
The Luminous Fish Effect: Getting fired forces Sheldon to ponder life outside physics, so Leonard has to take drastic action to snap his friend out of his reverie. (S1 Ep4) [AD,S]
The Dumpling Paradox: When Howard seduces Penny's friend and spends the night with her in Penny's flat, Penny asks if she can sleep on Leonard and Sheldon's sofa. (S1 Ep7) [AD,S]
The Hamburger Postulate: Leonard thinks he's been wasting his time on Penny, so he turns his attention to Leslie. Sheldon's uncomfortable with a change to his hamburger routine. (S1 Ep5) [AD,S]
The Middle Earth Paradigm: Penny's Halloween party puts Leonard, Sheldon, Howard and Raj through a demanding new test of their social skills. (S1 Ep6) [AD,S]
The Dumpling Paradox: When Howard seduces Penny's friend and spends the night with her in Penny's flat, Penny asks if she can sleep on Leonard and Sheldon's sofa. (S1 Ep7) [AD,S]
The Panty PiÄnata Polarization: Sheldon bans Penny from the flat for numerous minor infractions, so she retaliates. Howard and Raj search for the America's Next Top Model house. (S2 Ep7) [AD,S]
The Panty PiÄnata Polarization: Sheldon bans Penny from the flat for numerous minor infractions, so she retaliates. Howard and Raj search for the America's Next Top Model house. (S2 Ep7) [AD,S]
The Relaxation Integration: Amy tries to convince Sheldon that he has a more laid-back side. Raj and Stuart compete to woo Bernadette's new colleague Ruchi. (S11 Ep3) [AD,S]
The Explosion Implosion: Howard and Sheldon bond on a trip to the desert to launch a model rocket. Leonard is annoyed when his mother befriends Penny. (S11 Ep4) [AD,S]
The Collaboration Contamination: Sheldon and Raj ask Bernadette for advice about their jealousy when Amy and Howard decide to collaborate on a new project. (S11 Ep5) [AD,S]
The Proton Regeneration: Sheldon goes head-to-head with Wil Wheaton as they compete for the role of the new Professor Proton when the TV series has a reboot. (S11 Ep6) [AD,S]
The Fetal Kick Catalyst: Penny meets her fans at a comic book convention. Sheldon and Amy host brunch at Penny's flat. Howard makes an impulsive purchase. (S10 Ep6) [AD,S]
The Hot Tub Contamination: Leonard and Penny intervene when Sheldon and Amy have an argument. Howard and Bernadette are disturbed by unexpected guests. (S10 Ep5) [AD,S]
The Cohabitation Experimentation: When Amy's flat is flooded, she has to move out while it is being repaired and proposes a 'cohabitation experiment' with Sheldon. (S10 Ep4) [AD,S]
The Dependence Transcendence: Tensions rise when the guys struggle to complete their Air Force project on time and are forced to work around the clock. (S10 Ep3) [AD,S]
The Military Miniaturization: Howard has a meeting with Air Force representative Colonel Williams about the gyroscope he invented with Leonard and Sheldon. (S10 Ep2) [AD,S]
The Conjugal Conjecture: The gang face an awkward morning after Sheldon's mother and Leonard's father share an evening together. Penny's family arrive in town. (S10 Ep1) [AD,S]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24) [AD,S]
The Line Substitution Solution: Sheldon pays Stuart to spend the afternoon shopping with Amy so that he can queue up to see a special film screening instead. (S9 Ep23) [AD,S]
The Fermentation Bifurcation: The gang run into Penny's ex-boyfriend, Zack, at a wine bar. Bernadette, who can't drink, hangs out with Sheldon. (S9 Ep22) [AD,S]
The Viewing Party Combustion: During a get-together to watch TV at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. (S9 Ep21) [AD,S]
The Big Bear Precipitation: Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. (S9 Ep20) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16) [AD,S]
The Valentino Submergence: Sheldon and Amy host a special live Valentine's Day episode of their internet show Fun with Flags. Leonard and Penny grapple with getting older. (S9 Ep15) [AD,S]
The Convergence Convergence: Conflict arises when Leonard's recently divorced parents and Sheldon's devoutly religious mother are all in town at the same time. (S9 Ep24) [AD,S]
The Line Substitution Solution: Sheldon pays Stuart to spend the afternoon shopping with Amy so that he can queue up to see a special film screening instead. (S9 Ep23) [AD,S]
The Fermentation Bifurcation: The gang run into Penny's ex-boyfriend, Zack, at a wine bar. Bernadette, who can't drink, hangs out with Sheldon. (S9 Ep22) [AD,S]
The Viewing Party Combustion: During a get-together to watch TV at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. (S9 Ep21) [AD,S]
The Big Bear Precipitation: Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. (S9 Ep20) [AD,S]
The Solder Excursion Diversion: Sheldon makes a surprise revelation when Amy buys him a new laptop. Leonard and Howard lie to their wives to avoid an errand. (S9 Ep19) [AD,S]
The Application Deterioration: Leonard, Sheldon and Howard run into problems when they file for a patent. Emily reaches out to Raj after their break-up. (S9 Ep18) [AD,S]
The Celebration Experimentation: The gang persuade Sheldon to celebrate his birthday and invite a few special guests along to his party, in the 200th episode. (S9 Ep17) [AD,S]
The Positive Negative Reaction: When Bernadette makes a big announcement, Howard becomes convinced that he needs to start earning more money. (S9 Ep16) [AD,S]
The Valentino Submergence: Sheldon and Amy host a special live Valentine's Day episode of their internet show Fun with Flags. Leonard and Penny grapple with getting older. (S9 Ep15) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [AD,S]
The Empathy Optimization: The gang plan a Sheldon-free weekend in Las Vegas after coping with his constant demands, rudeness and ingratitude when he was ill. (S9 Ep13) [AD,S]
The Sales Call Sublimation: Penny gets more than she bargained for when Leonard meets a psychiatrist, while Sheldon and Raj make an astronomical discovery. (S9 Ep12) [AD,S]
The Opening Night Excitation: Leonard, Howard and Raj have an extra ticket for the Star Wars movie premiere but can't decide who they should give it to. (S9 Ep11) [AD,S]
The Earworm Reverberation: Sheldon is driven to distraction when he can't get a familiar tune out of his head. Howard and Raj find out that their band has a fan. (S9 Ep10) [AD,S]
The Platonic Permutation: At Thanksgiving, Sheldon and Amy hang out as friends at the aquarium, and Howard reluctantly agrees to volunteer at a soup kitchen. (S9 Ep9) [AD,S]
The Mystery Date Observation: While Amy's out on a date with a mystery man, Sheldon enlists Howard and Raj to help him find a new girlfriend online. (S9 Ep8) [AD,S]
The Spock Resonance: While he's being interviewed for a documentary about Star Trek character Mr Spock, Sheldon can't suppress his emotions about his split from Amy. (S9 Ep7) [AD,S]
The Helium Insufficiency: Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app for Amy. (S9 Ep6) [AD,S]
The Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [AD,S]
The Meemaw Materialization: Sheldon is thrilled when his beloved grandma 'Meemaw' comes to visit, but his excitement fades when she butts heads with Amy. (S9 Ep14) [AD,S]
The Empathy Optimization: The gang plan a Sheldon-free weekend in Las Vegas after coping with his constant demands, rudeness and ingratitude when he was ill. (S9 Ep13) [AD,S]
The Opening Night Excitation: Leonard, Howard and Raj have an extra ticket for the Star Wars movie premiere but can't decide who they should give it to. (S9 Ep11) [AD,S]
The Earworm Reverberation: Sheldon is driven to distraction when he can't get a familiar tune out of his head. Howard and Raj find out that their band has a fan. (S9 Ep10) [AD,S]
The Platonic Permutation: At Thanksgiving, Sheldon and Amy hang out as friends at the aquarium, and Howard reluctantly agrees to volunteer at a soup kitchen. (S9 Ep9) [AD,S]
The Mystery Date Observation: While Amy's out on a date with a mystery man, Sheldon enlists Howard and Raj to help him find a new girlfriend online. (S9 Ep8) [AD,S]
The Spock Resonance: While he's being interviewed for a documentary about Star Trek character Mr Spock, Sheldon can't suppress his emotions about his split from Amy. (S9 Ep7) [AD,S]
The Helium Insufficiency: Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app for Amy. (S9 Ep6) [AD,S]
The Perspiration Implementation: The guys take fencing lessons from Barry Kripke. Stuart struggles to attract female customers to the comic book shop. (S9 Ep5) [AD,S]
The 2003 Approximation: Sheldon sulks when Penny and Leonard announce that they're moving in together. Howard and Raj form a band to play at the comic book shop. (S9 Ep4) [AD,S]
The Bachelor Party Corrosion: The guys' science skills are tested when they get a flat tyre during Leonard's surprise bachelor party weekend in Mexico. (S9 Ep3) [AD,S]
The Separation Oscillation: Sheldon films a special post-break-up episode of Fun with Flags. Bernadette feels guilty about withholding a secret from Penny. (S9 Ep2) [AD,S]
The Matrimonial Momentum: Penny struggles with Leonard's confession that he kissed another woman. Sheldon doesn't know how to act when Amy breaks up with him. (S9 Ep1) [AD,S]
The Commitment Determination: Sheldon pressures Leonard and Penny to choose a date for their wedding while dealing with changes in his own relationship. (S8 Ep24) [AD,S]
The Maternal Combustion: Personalities collide when Sheldon and Leonard's mothers finally meet. Howard decides to 'man up' and do his share of the housework. (S8 Ep23) [AD,S]
The Graduation Transmission: Leonard is invited to make a speech at his old high school. Howard and Sheldon can't make a toy drone fly. (S8 Ep22) [AD,S]
The Communication Deterioration: Raj is asked to create a message for NASA to use if one of their missions finds alien life. Penny considers taking up acting again. (S8 Ep21) [AD,S]