Here is some new tech that has been developed by Digitas in France. Using a 3D camera, depth sensor and projector. They have been able to map a piece of paper and a variety of objects to manipulate/interact with an existing website.
I can see this being used in large experiential campaigns as well as interactive window displays without the expense of touch screens. Could be interesting as a training tool in schools identifying different objects a child might be playing with and displaying interactive information to suit.