3. 'This Is Spinal Tap'
Rob Reiner's This Is Spinal Tap was such a convincing mockumentary that to this day many people think that Spinal Tap is an actual band. Spinal Tap, however, was in on the joke, touring when the movie came out and writing some songs in the years since. Who knows? Maybe the people who think they aren't a real band have become the foolish ones.