This came out of me needing an excuse to write some Clojure, and wanting to model a simple coin-tossing game. What started as a guide to Clojure for busy programmers probably makes a right-sized holiday hacking project.
(One side point, that background is a little hard to read against; it actually started to give me a headache... :)
This is exactly the kind of next step I was looking for beyond the 4clojure and clojure koans stuff. I'll be working through it this weekend. Thanks!