Overtone, Clojure and Minecraft
Overtone is an open-source audio environment for programmable music. Clojure is a Lisp-family programming language that runs on the Java Virtual Machine. Minecraft is a game that you are probably aware of that also runs on the JVM. Integrate them together, and you get this.
This video by Joseph Wick is an example of live coding, where the musician-programmer enters code to produce music and visual effects. Here, Minecraft is used as the visualizer. You can see how changes to the code show up instantly in the game, synced to the music.
You can read more about how this was done here: http://blog.josephwilk.net/clojure/overtone-driving-minecraft.html