I've finally open-sourced an Archaeopteryx rewrite in Clojure using Overtone. It's called Arx. I wrote this last year but only just open-sourced it today. I had planned to make the code more idiomatic, and upgrade the drum samples, but I forgot all about it, so I figured I should just get on with it.
I also wrote a similar Clojure project in 2013 at WACM. It's called markov-bass-lines and it builds moombahton beats with a very entry-level Markov chain.