Maximum PC didn't like the idea of paying $12,000 for a Microsoft Surface. So what did they do? They made their own multitouch table PC for a fraction of the price.
Utilizing an array of infrared LEDs around the table, the guts of a PS3 Eye camera, a projector and some acrylic for the multitouch setup—along with a homemade wood cabinet and an old PC they had lying around (Core 2 Duo, 2 gigabytes RAM)—they fashioned together a multitouch beast for $350 that more or less mimics the surface experience.
The video runs through some of the demos available, which includes an ambient light/finger paint type program that can track all 10 fingers, a Pong-like game, and the usual photo shuffling, it's evident this was no half-baked project.
The project took a total of two weeks, and utilizes all open source software (Touchlib, AMCap, FlashOSC) to power the machine. For the entire lowdown (and tons more pics) on how this was constructed, definitely check out the post over on [Maximum PC].