This is incredibly refreshing and inspiring, congrats!
I don't see a lot of audio-related Ruby projects around. How did you implement the audio engine? A quick look in the source files seems to show it's all pure Ruby.
A nice extra feature would be to edit/save and update live, while the loop is running, but I don't know if pure Ruby can fit the bill. And this reminds me of a language I've heard a lot of good things about: Chuck [1], which allows you to modify the code live (apparently it's used in Smule's iOS apps). Has anyone here played with it?