The Big Bang Theory Season 2 Episode 21 : The Vegas Renormalization
Leslie Winkle ends her "friends with benefits" relationship with Howard, and he becomes depressed. Leonard and Raj decide to take him on a trip to Las Vegas, Nevada in order to cheer him up. Meanwhile, Sheldon, who has declined to go to Las Vegas, is delighted to spend the weekend alone. While in Vegas, a prostitute named Mikaela (Jodi Lyn O'Keefe) approaches Raj, and eventually he and Leonard decide to hire her for Howard with her giving him the Jewish girlfriend role-playing treatment. Howard soon realizes she is a prostitute, but nevertheless he thanks Leonard and Raj for setting up this "date". Meanwhile, Sheldon, having forgotten his apartment key, is forced to spend the night at Penny's apartment. In the end, Sheldon thinks he has a better understanding of the term "friends with benefits".