CBS

Season 1: Episode 17 - The Tangerine Factor

The Tangerine Factor: Penny finally breaks up with her boyfriend, giving Leonard the courage he needs to ask her out on a real date. She agrees to the date. However, before they actually go out, they both seek the “wisdom” of reluctant advisor, Sheldon, on separate occasions. The Tangerine Factor is the first season finale of “The Big Bang Theory.”