: This episode was heavily promoted as a celebration of the show's longevity.
: After imagining a disastrous outcome where they break up again, Leonard decides to ask her out anyway, concluding that he can't know what will happen unless he tries. Episode 13: The Recombination Hypothesis
: While Leonard frets over the date, Sheldon is preoccupied with his own social standing and trivializes one of Amy Farrah Fowler's accomplishments, forcing Penny to intervene and help him apologize. Trivia & Production : This episode was heavily promoted as a
: Leonard sees Penny through a doorway and, on a whim, asks her to dinner. She accepts, leading to a romantic evening that starts well but quickly devolves into an argument about the "beta test" of their relationship. on a whim