monome.

My friend from New York came in town last week, and brought an expensive toy with him - the monome, a beautifully minimalistic interface that does all sorts of neat things (music performance, tetris and more). The open-source software can be used and developed by anyone. It's pretty amazing, and the lovely silkscreened packaging makes it even better.

See an interview with developer Brian Crabtree here and see it in action here.