“Christ, you're dragging me out for that? I can tell you what they'll say. They'll drag out the Four Horsemen of the Infocalypse: kiddie porn, terrorists, pirates, and the mafia. They'll tell us that any tool for communicating that they can't tap, log, and switch off is irresponsible. They'll tell us we're stealing from ISPs. It's what they say every time someone tries this: Philly, New York, London. All around the world same song.”

Source: Maybe, Maybe Not

Source: The Bridal Season

Source: Time Enough for Love

Beat It
Thriller (1982)

Source: The Lost World

Presidential debate http://www.pbs.org/newshour/bb/politics/july-dec00/for-policy_10-12.html (11 October 2000).
2000s, 2000

Credited to Shaw in the lead in to the mockumentary C.S.A.: The Confederate States of America (2004) and other recent works, but this or slight variants of it are also sometimes attributed to W. C. Fields, Charlie Chaplin, and Oscar Wilde. It might possibly be derived from Shaw's statement in John Bull's Other Island (1907): "My way of joking is to tell the truth. It's the funniest joke in the world."
Another possibility is that it is derived from Shaw's characteristic of Mark Twain: "He has to put things in such a way as to make people who would otherwise hang him believe he is joking."
Variants:
If you are going to tell people the truth, you'd better make them laugh. Otherwise, they'll kill you.
If you're going to tell people the truth, you'd better make them laugh. Otherwise, they'll kill you.
Disputed

Us
Soviet Kitsch (2004)