Here’s a video of TouchWall and Plex in action.

And some more info from CrunchGear:

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. Early prototypes, say Pratley and Sands, were made, simply, on a cardboard screen. A projector was used to show the Plex interface on the cardboard, and a the system worked fine

And also, Microsoft doesn’t have immediate plans to turn this into a product. Let’s hope that changes. Think of all those CSI labs that are just waiting to file those budget requests.