With a wiimote and a bit of processing code you can turn any projection surface into an interactive multitouch screen. LED keychains modified with infrared LEDs serve as input devices. The wiiMultitouchServer is compatible with the IDEO Flash Multitouch API, so you can build any type of Flash multitouch application and run it on this type of system.

Here we're using it for it's most important application--Pong!