Gamasutra has a good piece from 2004 about alternative game controllers.
very once in a while a truly unique input device, either co-opted from another industry or a completely new invention, comes along that makes people sit up and take notice. Even with the computer industry in the doldrums, the past year has seen the launch of a half-dozen different input devices, and if the devices I saw in Kentia Hall at this year's Electronic Entertainment Expo was any indication, it looks like the next year or two in games is going to be very interesting.The game controllers there sparked some ideas of how they could be used for creating innovative games, and bringing back a few classic toys of our youth. Some of these concepts may be little more than interesting distractions, but I hope this article makes a few game designers--as well as the controller manufacturers--sit up and start thinking about designing some cool games to go along with them.
It focuses on accelerometers, Virtual Arm Wrestling, force feedback and so on. My favorite is the katana sword game controller ( from Hori Japan):
