I saw this while surfing the net today. Looks like it would be fun. Probably not very practicle... but fun. I could see something like this being very useful for home theater needs.

This is a 50'' multitouch surface that my group made for our fourth year design project at the university of waterloo. The project is called TouchMe. The whole system was built by us, starting from a large piece of plastic. Took us months... cool huh?
Check here for more info

http://www.youtube.com/watch?v=cxBclX1xuR4