I had a chance to check out the Cosmic Hand Dance Actualization Machine by Nicholas Rubin at the ITP Winter Show 2008. It's a really interesting interactive display that uses a unique domed display. Check out the link for a lot more information about this amazing interactive artwork. Thanks Nicholas!

The Hand Dance actualization machine consists of a frosted hemisphere with an array of infrared distance sensors mounted along the rim and underside. It controls a Processing sketch of shimmering, psychedelic imagery that is projected onto the surface from underneath. The IR sensors allow the user to move their hands spatially within the volume to control specific aspects of the animation.

More about making the The RV10000: Cosmic hand dance actualization machine [ITP page]