Visions of the Amen, a voice-responsive kinetic sculpture by artist Mitchell Chan (demonstrated in this video by soprano Ashleigh Semkiw). The software is written in Processing, the hardware is controlled by the ArtBus interface being developed at the School of the Art Institute of Chicago. Kind of like a real-world oscilloscope.
Pretend to be Radiohead with this Instructable guide to 3D light scanning using a projector, camera, and a bit of Processing! This is designed to create the visualization seen in the video above, but you could also use the point data for output on a 3D printer, animation package, etc. Neat.