Google has released software that allows developers to create interactive physical rooms.
Cameras installed in the ceiling can track people (or other things) and the room would react with certain responses depending on the position of a person or object. In a published example, a room followed a person by showing colored circles on the floor.
Called "Interactive Spaces", the software was developed by Google and Rockwell LAB. It is currently available as an initial source release with a 47-page documentation and a final release is planned to be made available sometime in the future. Interactive Spaces is written in Java and can run on any platform that supports the language.