If you like experimenting with music, you may find that Otomata is just about the best thing ever. Created by Batuhan Bozkurt, Otomata is an online generative sequencer that produces "sound events" through the movement of cells. Visitors can move the cells in different ways to create a range of sounds and textures, and it can be quite addictive. There's also a demonstration video here that will show users how to get started. This version is compatible with all operating systems.