To begin, I’d like to report some pointers about the background of multitouch and gesture recognition interfaces, a good point from which to start when designing them.
Bill Buxton is a researcher who’s been working on multitouch since 1984. He compiled this interesting overview.
At the MTG I had the pleasure to meet Shahram Izadi, who held a conference called “Hands-on Computing” talking about the history of the user interfaces, the keys for their development, and the state of the art about multitouch in its larger extent.
“Interactive Gestures: Designing Gestural Interfaces”, is a new book by Dan Saffer. Its first chapter is publicly available as a free sample and it also features the NUI group.