The Big Bang Theory: Season 1

A pair of socially awkward theoretical physicists meet their new neighbor Penny, who is their polar opposite.

Penny is furious with Leonard and Sheldon when they sneak into her apartment and clean it while she is sleeping.

Leonard gets upset when he discovers that Penny is seeing a new guy, so he tries to trick her into going on a date with him.

Sheldon's mother is called to intervene when he delves into numerous obsessions after being fired for being disrespectful to his new boss.

Leslie seduces Leonard, but afterwards tells him that she is only interested in a one-night stand.

The guys are invited to Penny's Halloween party, where Leonard has yet another run-in with Penny's ex-boyfriend Kurt.

When Howard hooks up with Penny's old friend, his absence in the gang causes problems for the rest of the guys.

When Raj's parents set him up on a blind date, he finds he can talk to women with the aid of alcohol.

Leonard and Sheldon's friendship is put to the test when Leonard wants to present a paper they co-authored at a physics convention, but Sheldon doesn't.

Leonard lies to Penny so he and Sheldon can get out of watching her perform, but Sheldon believes that the lie has too many loose ends, so he comes up with a new, unnecessarily complex one to replace it.

When Sheldon gets sick, Leonard, Howard and Raj go AWOL, leaving a reluctant Penny to deal with him.

Sheldon decides to give up his work and focus on other tasks when a 15-year-old prodigy joins the university, so the other guys come up with a plan to get rid of him.

Sheldon becomes so intent on demonstrating his intellectual superiority over the other guys that they kick him off the Physics Bowl team and replace him with his nemesis, Leslie.

Penny gets mad at the guys when their full scale model of a time machine causes her to miss work, which prompts Leonard to give up all of his nerd memorabilia.

Leonard, Howard and Raj fight over Sheldon's twin sister when she arrives in town. Raj takes part in a drug trial to suppress his selective mutism.

When Penny learns that Leonard has never had a birthday party, she and the rest of the guys plan a surprise party for him.

After a bad breakup, Penny finally agrees to go out on a date with Leonard, however they both develop doubts and turn to Sheldon for advice.