Season 7, Episode 8 - The Itchy Brain Simulation
Aired November 14, 2013
When a past mistake of Leonard's comes to light, he's surprised that Sheldon promises not to make a big deal out of it. Sheldon instead makes Leonard walk a mile in his shoes to learn what it feels like to be tormented by trivial matters. Meanwhile, Penny embarrasses Raj when she confronts his ex-girlfriend, Lucy.