The Light and Gravity Show is the one of the best multi-media exhibits I have seen in Second Life. Top artists, including Bryn Oh and Ub Yifu have produced individual exhibits in a huge multicolored sim-sized pavilion. You can read about it here.
Make sure your light settings are on midnight, or Barcelona, or something similarly dark to get the best out of the exhibit. Pick up a HUD to explain each of the artists exhibits at this location below:
This You Tube video shows one of the main exhibits in detail: