Just start hitting keys (turn sound on first). This is a lot of fun. The only thing I with the developer would have done is make the sounds polyphonic. In other words, if I hit two (or more) keys at the same time, I’d like to hear their sounds simultaneously.

Still, this was interesting and inspiring.

UPDATE: Even more fun on the iPhone and iPad. The interface is all touch (of course) and multiple touches play simultaneously. Huzzah!!! [Hat tip to Kip Beatty]