This is a great video of Nicholas Rubin's Physical Computing project, in which he built a volumetric interface and projection surface. Rubin is a graduate student at NYU's Interactive Telecommunications program.
Cosmic Hand Dance Actualization Machine - HD from Nicholas Rubin on Vimeo.
The following quote from the video was posted by Doug Fox, of Great Dance/Kinetic Interface:
"In building this object I used as my theoretical foundation a practice called "glowsticking" that exists predominantly in rave and underground electronic music culture. Glowstickers, at least the talented ones, have cultivated the unique ability to twirl their glowsticks in mid-air and actually generate continuous, dynamic, 3D imagery in space. This is then observed by other party-goers whom might be near them. It usually happens spontaneously on the dance floor as opposed to being strictly a performance activity."