I just caught a demo of the Tactable multitouch surface, which grew out of an MIT Media Lab project. It’s an impressive product, a mid-sized table with a sharp projector set underneath the glass. It uses an array of moderate-resolution optical sensors to tell where it’s being touched, and the sensors have variable focus, so they can sense 3D gestures over the surface as well as contact with the surface itself. The projector’s good and bright, and the picture looked good in a well-lit room (albeit a darker corner of same). And being optical, the sensors can also recognize objects laid on the surface, reading bar-codes, text, shapes, etc.