Microsoft's Surface tables are sweet but they have two problems: They're huge pieces of furniture and they cost a lot. Turns out, they could solve both problems by turning the system upside down, using a portable camera/projector and any surface.
Surface tables are just cameras and projectors pointing upward at a tabletop of glass. Since both of those mechanisms have become totally portable, Microsoft Research conceived of a prototype that is, effectively, portable. The advantage, beyond mobility, is that the camera can read depth in free space, so it can do 3D activities, almost like a baby Natal.
Here, in this functional proof-of-concept, you can see a drums app, where both hand interaction and stick interaction are measured when your hands are between the camera and the projection. (On a regular Surface, you'd have to touch the screen to interact.)
In the explainer shot below, you can see a more real-world scenario, where you'd set your phone on a table at a restaurant and it projects pictures and documents out, so that you and others can interact with them. We're already seeing projectors built into phones and cameras, so it may just be a matter of time before this appears. Windows Phone 8 maybe? Microsoft, of course, isn't promising anything at this point. [Mobile Surface]