Ha! A friend of mine gave me one of those things almost ten years ago. I still have the thing in the attic. It plugs in the audio jack and is a low pass amp hooked to a voice coil strapped to your back - all the bass becomes force feedback. It worked great with MechWarror 3 back in the day, but the thing is really noisy and distorted. I kind of wished it had an adjustable crossover to tweak it for each game. I may pull it down just for fun...