If you'd like to have your own multi-touch whiteboard, drafting table, or tablet PC. You can make one using a Wii remote and some IR leds pens. The IR camera in the Wiimote will track the location of the pens. With a little bit of software, you can map the camera data to the display position so you can use the stylus just like a mouse.
The software is available to download from my website at http://johnnylee.net