The Big Bang Theory: Season 1, Episode 2

1 - 2: The Big Bran Hypothesis

A Superman movie marathon is disrupted when Penny asks the guys to sign for a package that may be delivered while she’s gone. But when the guys discover that the package is huge, they understand it’s going to take some hard work to get it up all the stairs. When they finally do so and manage to get into Penny’s apartment with the spare key she gave Leonard, Sheldon is shocked about how messy her apartment is, and decides to clean it during the night while Penny is sleeping. However, when Penny wakes up, she is furious that they were in her apartment and Leonard is sad while she is angry at them.