Dan Maynes-Aminzade describe some simple computer vision-based techniques he developed that enable members of a large audience to participate, either cooperatively or competitively, in shared entertainment experiences. These techniques allow groups of hundreds of people to control onscreen activity through simple activities like leaning left and right in their seats, batting around a beach ball, or pointing laser pointers at the screen. He will show video of some past interactive audience shows, give a live demo, and finish by showing some of his more recent projects involving camera-based input, including a class he is teaching at Stanford called "Designing Applications that See" and a large-scale interactive digital mural developed for the San Jose Museum of Art.

http://dorkbot.org/dorkbotsf/archive/200703/