Ah, harkening back to the days of my youth, I remember the Nintendo Entertainment System had a ton of cool alternative controllers like the PowerPad (kinda the grand daddy of the Dance Dance Revolution), the PowerGlove, and the funky Uforce (infrared motion detectors). I thought some of the controller ideas were kinda neat, but they never really had great game support in my opinion.
O’reilly Make (which I really need to subscribe to soon) has a fun article about turning these wacky controllers into MIDI musical instruments. Cool idea! With some interface hacking and some glue code built a pretty cool instrument. I’d really like to see a video of some real time music creation.