Between Natal and Microsoft Surface, Microsoft research seems to explore new way of interaction.
It's pretty cool to see those concept based on a camera and a pico projector that allow you to use any non reflective surface as a virtual desk.
It's seems that works already as a concept :
The result is quite nice and look promising. Imagine that you can modify schedule directly with your colleague in the meeting room by viewing the overlap of each person calendar... It could be seen as a ultra portable way of sharing information and record things.