This looks like some really fun stuff
http://www.wired.com/gadgets/mods/multimedia/2009/03/gallery_instruments?slide=22&slideView=10
“Greg Kellum uses two ancient technologies as an interface for his hypermodern Touch Plane instrument: paper and ink. An overhead camera and table-clamped infrared lasers track finger movements with only almost no latency, allowing him to use controls that are printed on a piece of paper”
