http://www.gametrailers.com/remote_wrap.php?mid=701341
Deep within the 2001 GameCube game Super Smash Bros. Melee lurks a hidden playable character – the game’s boss, Master Hand. By performing a deft controller maneuver that essentially tricks the game into grabbing Master Hand’s player data before it is overwritten (watch the video), you can flick characters off the screen and even smash them while you fly through the air like superhand.
It’s crazy that it took nine years for this to come to light, although users hinted at the trick, called the Name Entry Glitch, back in 2008.