As early as June 2007 i had written a small article on "Microsoft Surface" the real magic. Well it now seems that the 'Surface' table wasn't big enough.
Microsoft envisions your walls as computers. At the CEO Summit 2008 Bill Gates demonstrated the "TouchWall", a new hardware technology from Microsoft that creates a touch based white board interface that lets users interact more naturally with data and applications on their computer. However as per Microsoft the two products (Microsoft Surface and TouchWall) are completely different.
Surface is a multi-touch and vision system that uses cameras to sense what is on the table, where it is and what it is doing. Whereas TouchWall consists of three infrared lasers that scan a surface. A camera notes when something breaks through the laser line and feeds that information back to the Plex software. While Surface retails at around $10,000, for TouchWall is just "hundreds of dollars".
Heres a quick video demonstration of "TouchWall"