Using a couple of homemade infrared pens, a Wiimote, and some software he wrote, Johnny Chung Lee of Carnegie Mellon University has come up with, what must be, the coolest Nintendo Wii hack ever. Since the Wii tracks IR lights, Lee found that practically any surface — a projector screen, a tabletop, an LCD screen — could be turned into a multi-touch screen reminiscent of the iPod Touch or Microsoft Surface.
[Low-Cost Multi-touch Whiteboard using the Wiimote – YouTube]
For those do-it-yourself types out there, the software can be downloaded here.