"The Dumpling Paradox"  (Season 1 | Episode 7)  22:0
Penny's slutty friend, Chrissy (Brooke D'Orsay) from Nebraska, is in town and is seduced by Wolowitz. The pair ends up taking over Penny's apartment, forcing her to sleep on Leonard and Sheldon's couch.
Original Air Date: 11/5/2007