[s5e13] The Recombination Hypothesis -

: Most of the episode—including the date, an ensuing argument, and their eventual reconciliation—is actually a hypothetical scenario (a daydream) playing out in Leonard's head as he contemplates whether asking her out is a good idea.

: After Leonard asks her out, Penny accepts, much to the surprise of their friends. [S5E13] The Recombination Hypothesis

The episode follows Leonard as he impulsively asks Penny out for dinner, leading to a sequence of events that highlights his tendency to over-think everything. : Most of the episode—including the date, an