In 2006, before Kinect and maybe even before Wii, gamer Niel de la Rouviere decided to make a motion-controller for Quake III. He says he was bored; I say that Niel de la Rouviere, armed with masking tape, was efficient.
He uploaded a video of his makeshift contraption to YouTube yesterday. I'm impressed that it works, but I don't think I'd like to play a first-person shooter that way. If anyone out there wants to recreate de la Rouviere's keyboard-gun-tape controller, let us know how it goes.
Quake 3 Low Budget Motion Sensor [YouTube]