Howard uses a robotic arm for his own pleasure. Penny assists Sheldon with his first date.
Sheldon realizes that by the time he downloads his consciousness into a robot body, he'll be dead, so he tries to make himself live longer.
When Sheldon "breaks up" with Amy, the guys worry as he tries to find a companion to replace her.
An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.
Leonard realizes he's the only one without a girlfriend, while Sheldon wants to get rid of his.
A visit from Raj's sister coincides with Leonard becoming secretive.
Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.
The guys camp out in line to see a movie, but have their plans jeopardized by Wil Wheaton. Penny and Bernadette invite Amy over for a slumber party.
Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.
Amy crushes on one of Penny's dim ex-boyfriends. Raj and Wolowitz argue over who'd be the better superhero.
The guys rope Zack into their costume contest entry as the Justice League.
Leonard's friendship with Sheldon becomes strained when they both fight over an idea for a smartphone application.
A science convention at a hotel leads to Bernadette running into an ex-boyfriend and Wolowitz worrying he can't quite compare.
Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friend's girlfriend.
An aged, but wealthy, Caltech donor wants sex from Leonard in exchange for another large donation.
Wolowitz finds himself having to choose between Bernadette and his mother. Leonard has another rendezvous with Raj's sister Priya.
Realizing Leonard is the center of the gang, Sheldon seeks to form a new group of friends of which he can be the center.
Sheldon is baffled by Wolowitz's magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.
When Sheldon has his online gaming account hacked and his character stolen from, the guys team up to discover out who did it.
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.
Sheldon goes dancing with the girls while Priya tries to break down the roommate agreement using legal theory.
Raj hopes to cure himself of his inability to talk to women. Meanwhile, Penny recruits Bernadette to spy on Leonard and Priya.
Howard musters up the courage to tell his mother that he is going to marry Bernadette. The news doesn\'t sit well and she ends up in the hospital.
When Bernadette receives her Ph.D., the guys take joy in reminding an emasculated Wolowitz that he is the only one in their group who isn't a doctor. Meanwhile, Koothrappali becomes Sheldon's new roommate after hearing Leonard and Priya engaging in a "Star Trek" bedroom fantasy.