It's a week for multitouch tables, with the latest DIYer to turn their hand to creating a low-cost interactive surface being 17-year-old Bridger Maxwell. His OS X-powered table was built for Central Utah Science and Engineering Fair, and uses the usual array of LEDs, acrylic platter and infra-red camera to recognise multiple points of contact. Currently the table works as an image browser.
Since Bridger needed something suitably geeky and non-personal to display, he picked the excellent xkcd comics. He then developed an image browser with search functionality that uses Core Animation to display and manipulate the multiple layers. If you're interested in trying it yourself, he's even made the app available for download (on PC and Mac, no less).
I'm still looking for a video of Bridger's table in action, so if you see one please do mention it in the comments. Check out the other multitouch table we've mentioned this week, Eyebeam's open-source Cubit project.