Season 1: Episode 14: Kiss and Yell
While sharing stories about the first time they met, Christine learns that Kim kissed Jimmy while he and Christine were going out. As a result, Christine refuses to sleep with him that night. Greg, meanwhile, doesn't care what Kim did with Jimmy, as he claims to have kissed more than his share of girls at the time. Kim presses him into revealing what number "more than his share" is, and then laughs when he says it's fifty. Determined to make Kim believe him, Greg sets about making a list of the names of all fifty girls. Greg's completed list -- of merely forty-nine girls -- turns Kim around so she's no longer amused at Greg. Instead, she's disgusted with him. Jimmy is able to calm Kim down by telling her that fifty isn't a high number at all, when most guys his and Greg's age kissed five hundred girls. Greg would feel inadequate at Jimmy's machismo if he weren't already feeling inadequate over having not even made it to fifty. To spite Jimmy and even the score, Christine kisses Greg, taking him to the magic number. Jimmy brags that they aren't even because she kissed Greg out of spite, while the kiss between him and Kim was passionate and meaningful. Kim reveals the cold, hard truth to Jimmy -- the reason she kissed him all those years ago was to get even with Christine for touching her stuff.