Volume
Went over to South Kensington today to see a couple of exhibits at the V&A. Out in the back garden they had an interesting exhibit, Volume, which is a rather cool interactive audio/visual display.
The exhibit consists of around 46 music columns arranged in a lattice. Multi-colour LEDs are mounted on the front of each pole, and at the top and bottom there are speakers mounted.
Each column is an instrument, one might be a bass drum, another might be some strings, a group of poles might be some synth sounds. As each column plays a sound, the sound is represented visually by the LEDs. Together the columns form a song that plays in 46 surround sound (a bit more spatial than your THX, DTS and Dolby systems!).
For some tracks the columns are activated by walking up to them. If no one walks up to them they hibernate. This gives you a unique sound, by you and everyone else, walking through Volume.
The exhibit is a collaboration between United Visual Artists (UVA) and Robert Del Naja (from Massive Attack).
http://www.vam.ac.uk/collections/contemporary/volume/index.html