Season 3, Episode 3 - The Gothowitz Deviation
Aired October 5, 2009
Howard and Raj try to meet women at a Goth nightclub. Meanwhile, Leonard is disturbed when Sheldon attempts to retrain Penny with chocolate-based positive reinforcement to eliminate what he considers her annoying traits.
Season 4, Episode 4 - The Hot Troll Deviation
Aired October 14, 2010
Howard is embarrassed when the creepy reason behind his break-up with Bernadette is revealed. Meanwhile, a spat between Sheldon and Raj gets ugly as they engage in office warfare.
Season 8, Episode 9 - The Septum Deviation
Aired November 13, 2014
Sheldon is troubled when Leonard decides to get minor surgery performed on his nose. Sheldon tries to convince Leonard not to get the surgery in case he doesn't make it. Meanwhile, Raj is distraught when he finds out his parents have divorced just before their 40th wedding anniversary, causing Howard and Bernadette to pay more care to their own relationship.