Q: How many Kennedys does it take to screw in a lightbulb?
A: None, at least until we get some corroborating witnesses.

Q: How many Kennedy assassination conspiracy theorists does it take to screw in a light bulb?
A: 15-One to screw it in, five to say he acted alone, one to say that someone hidden in the ceiling helped, one to film it, one to do an intense examination of the film and conclude that a) it was tampered with and b) it proves that the first screwer did not act alone, one to insist that the bulb was altered after it was unscrewed, three tramps to walk across the room an hour later, one to insist LBJ really screwed the bulb in, and one to accuse all the others of being disinformation specialists.