Monkeys in your pocket
iMonkeypants is an iOS app (for iPhone and iPad) of interactive electronic music that is available on the App Store. The music is written in code in the same programming language as I use for Headless Monkey Attack, but the interactivity comes from the accelerometer of the device, which means you get to control the interactive features by moving your phone around.
The music is considerably simpler than Latency in the System, in part because mobile devices don't have as much computing power as my laptop (and especially didn't when I was developing iMonkeypants). You can read more about it and watch a video on my other site.