Billy Knight is a longtime professional comedian who has clearly fallen on hard times. His act is made up of sardonic one-liners and observations about life and various personalities in New Vegas. It is implied that he was once a well-known comic, but his desperation causes him to sharply question his worth to a club.
If recruited for Torini, Billy performs his act at the Aces nightly between 4:00 P.M. and 6:00 P.M.
If you listen to all of his jokes, he will make a crack about being served human meat at the Ultra-Luxe, foreshadowing a quest with them. The joke is somewhat similar to the cannibalism joke that the robotbutlers tell in Fallout 3 ("Two cannibals are eating a clown. One cannibal turns to the other and asks, 'Does this taste funny to you?'").
The Tops sign bills him as the "King of Zing!"
During the course of his routine, Billy will make a joke about Tops owner Benny paying his salary. Billy will make this joke even if Benny is dead or has fled the Strip while other non-player characters in the theater are talking about the mobster's recent disgrace.
Billy may also make a joke about Benny paying his salary even if he is still working on the street.
Billy will continue to joke about Securitrons having policemen faces after they are upgraded to the Mark II software, which replaces the policemen with soldiers among other changes.