One of the things I do is teach a Music Appreciation class at Macon State. As an introduction to 20th century music ideas, we record two pieces - one demonstrating chance music {i.e. aleatoric} and one demonstrating minimalism.
These aren't traditional pieces in ANY sense of the word, but it IS a lot of fun to do, and every classes' version sounds completely different.
You can take a listen to several years worth of these recordings over at Last.fm:
http://www.last.fm/music/Tom+Rule/Music+Appreciation+Experiments
