So here is another video from CeBIT I found which shows a 'Mixed Reality Interface'. Basically there is a smooth table with various objects on it which are also represented in 3D space in the screen behind the table. So when you move the block or ball that is on the table it also moves that object inside the virtual 3D space on the monitor. I don't know if they have some kind of position tracker in (or under) each object or it reads objects dynamically via a camera or some such. There is also a camera object which the guy can move around on the table and it moves the view in the virtual 3D space around as well. I was trying to come up with some real world applications for this kind of thing and some of the things I came up with were: a real time battleplan interface for the military (think minatures in WWII movies), creating virtual 3D movies ala stop motion but you're moving the realworld objects around for the virtual world camera, and possibly air traffic control. It would also make a pretty cool video game interface. The host site has a link to the creaters of the interface in the video and a link to the guy who captured the video.