Season 5: Episode 7 - The Good Guy Fluctuation

The Good Guy Fluctuation: ­Leonard meets a really cool girl, Alice, in the comic book store who immediately expresses an interest in him. The more time he spends with her, the more conflicted he feels about his relationship with Priya. In the end, he confesses to Priya that all he and Alice did was kiss and it will never happen again but Priya tells him she also messed up by sleeping with her ex-boyfriend. They both agree that perhaps the long-distance thing isn't working out so well. In honor of Halloween, the guys pull pranks on Sheldon throughout the episde. He tries to retaliate but they always seem one step ahead.