The Big Bang Theory

After Sheldon’s mother and Leonard's father share an evening together, everyone deals with an awkward morning the next day.

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

Tensions rise when the boys struggle to complete their government project on time and Sheldon tries an energy drink to stay

When Amy’s apartment floods, she proposes a “cohabitation experiment” with Sheldon. Also, Howard and Bernadette are upset when

Leonard and Penny must separate a quarreling Sheldon and Amy when their cohabitation does not go as planned, and Sheldon

Penny is surprised to learn she has fans of her performance in "Serial Ape-ist" when she attends Van Nuys Comic Con with

In order to continue living with Sheldon, Amy lies to him about repairs being made to her apartment and they host an "on

After a successful experiment combining their genes, Sheldon will stop at nothing to convince Amy they should procreate. Also,

When Bert, a Caltech geologist, wins the MacArthur Genius fellowship, Sheldon is overcome with jealousy. Also, Wolowitz finds an

Sheldon and Leonard try to divvy up their shared belongings, but can’t agree on anything. Also, Koothrappali and Stuart fight to

Howard and Bernadette welcome their new baby and Sheldon and Amy celebrate Amy’s birthday.

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to

When Penny feels that Leonard is taking her for granted, she decides to go on a spa weekend with Amy. Also, Wolowitz and

Sheldon beta-tests an MIT invention after hearing it can help him read people’s emotions. Also, Leonard can’t hide his feelings

Leonard and Wolowitz try to distract Sheldon when he slows the progress of their guidance system. Also, Penny and Amy take

Sheldon and Amy have their first fight since moving in together, and Koothrappali is shocked at the realities of financial

With Koothrappali cut off from his father’s fortune, he appoints Sheldon to help him get out of debt. Also, Penny considers

When Raj moves out of his apartment, Leonard and Penny offer him Sheldon's old room.

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

Sheldon pushes himself to the limit when he collaborates on projects with Leonard and Wolowitz as well as Amy on the same day.

Howard and Bernadette have a hard time leaving Halley in day care when Bernadette returns to work. Also, Bert introduces the

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

After Leonard, Sheldon and Wolowitz celebrate the completion of the top secret air force project, they are met with an

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