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Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...

About the Show

Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...

Series 5 Summary

This series brings the sound of wedding bells and more is discovered about the complicated lives of Sheldon, Leonard and their socially dysfunctional friends.

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    Episode 1 - The Skank Reflex Analysis

    Penny worries that she's screwed things up with her friends after her night with Raj. Meanwhile Sheldon takes command of the paintball team.

  • The Big Bang Theory: Sheldon

    Episode 2 - The Infestation Hypothesis

    A battle of wills between Sheldon and Penny leaves Amy in the middle. Leonard tries to spice up his long-distance relationship with Priya.

  • The Big Bang Theory

    Episode 3 - The Pulled Groin Extrapolation

    Leonard goes as Amy's date to a colleague's wedding. Howard tries to convince Bernadette to live with his mum after they get married.

  • The Big Bang Theory: Leonard

    Episode 4 - The Wiggly Finger Catalyst

    Raj is upset that he's the only one of the four guys not in a relationship, so Penny sets out to find him the perfect date.

  • The Big Bang Theory: Penny

    Episode 5 - The Russian Rocket Reaction

    Sheldon's old nemesis Wil Wheaton returns and invites everyone to a housewarming party. Sheldon threatens to 'de-friend' Leonard if he goes.

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    Episode 6 - The Rhinitis Revelation

    Sheldon's mum visits and soon becomes a firm favourite with his friends, much to Sheldon's annoyance.

  • The Big Bang Theory: Leonard and Bernadette

    Episode 7 - The Good Guy Fluctuation

    Leonard questions his feelings for Priya when he kisses a girl he meets in the comic book store.

  • The Big Bang Theory: Sheldon

    Episode 8 - The Isolation Permutation

    Amy is heartbroken when she finds out that Penny and Bernadette have been shopping for bridesmaids dresses without her.

  • The Big Bang Theory: Amy and Bernadette

    Episode 9 - The Ornithophobia Diffusion

    Leonard and Penny attempt to hang out without anybody else around, while Sheldon faces his fear of birds.

  • The Big Bang Theory: Howard

    Episode 10 - The Flaming Spittoon Acquisition

    Stuart from the comic book shop asks Amy out on a date. In jealousy, Sheldon asks her to be his girlfriend.

  • The Big Bang Theory: Sheldon and Bernadette

    Episode 11 - The Speckerman Recurrence

    Leonard confronts the man who bullied him in high school, while Penny realises she did her fair share of tormenting in the past.

  • Howard and Bernadette

    Episode 12 - The Shiny Trinket Maneuver

    When Sheldon is dismissive of Amy's career, Penny, Raj and Leonard teach him that sometimes it's a good idea to pretend to care about things

  • Penny

    Episode 13 - The Recombination Hypothesis

    In the 100th episode of the US sitcom, Leonard and Penny agree to give their relationship another chance, but they soon start to argue again

  • The Big Bang Theory

    Episode 14 - The Beta Test Initiation

    Leonard and Penny put their relationship through a 'beta test' and report problems they have with each other as 'bugs', while Sheldon and Amy seek internet fame

  • Leonard and Sheldon

    Episode 15 - The Friendship Contraction

    After Sheldon keeps him awake all night, an irate Leonard decides that he needs to break the roommate agreement, which formally ends their friendship

  • Leonard and Penny

    Episode 16 - The Vacation Solution

    Sheldon helps Amy in her biology lab after he is forced to use up two weeks of holiday, but he is bored by the tasks she gives him

  • Amy

    Episode 17 - The Rothman Disintegration

    Sheldon and Kripke argue over who should get Professor Rothman's vacant corner office. Amy buys Penny some art to celebrate their friendship.

  • Bernadette

    Episode 18 - The Werewolf Transformation

    Sheldon's well-organised world is turned upside down when he learns that the barber who has cut his hair for years is ill in hospital

  • The Big Bang Theory: Amy and Sheldon

    Episode 19 - The Weekend Vortex

    Amy is upset when Sheldon breaks his promise to accompany her to her aunt's birthday party in order to join the guys for a video game marathon

  • The Big Bang Theory: Sheldon

    Episode 20 - The Transporter Malfunction

    Penny buys Leonard and Sheldon some Star Trek memorabilia but she is irked when they refuse to remove the toys from their packaging

  • The Big Bang Theory: Stephen Hawking and Sheldon

    Episode 21 - The Hawking Excitation

    When Stephen Hawking comes to lecture at the university, Howard is given the task of maintaining his wheelchair, making Sheldon green with envy

  • The Big Bang Theory

    Episode 22 - The Stag Convergence

    Leonard, Sheldon and Raj throw a bachelor party for Howard, during which some stories about his sexual history are accidentally revealed

  • The Big Bang Theory

    Episode 23 - The Launch Acceleration

    When Nasa inform Howard that his space mission has been rescheduled to an earlier date, he tries to use the wedding as an excuse not to go

  • The Big Bang Theory: Leonard and Sheldon

    Episode 24 - The Countdown Reflection

    In the last episode of season five, Bernadette decides that she wants to get married to Howard before his Nasa space mission