Bro just doesn't know how to be retired. Jay Leno, whose audacity to displace his replacement Conan O'Brien started "the war for late night," visited his second replacement to tell a few monologue jokes and relive his former glory. Leno brought back some of his signature edginess, with jokes like, "A priest, a rabbi, and a minister walked into a bar, and then burned it down for the insurance money." 

Party like it's 2011 right here:

Sources: The Tonight Show Starring Jimmy Fallon