The March 2003 issue of Discover magazine had an article about Tim Blackwell's investigations of "swarming" behavior when creating computer-generated music. Blackwell is attempting to allow a computer to improvise - riff - music by mimicing bee swarms. Blackwell's personal site has more detailed descriptions of his work, as well as song samples (most require - gag - Real Player, but there are a few MP3s). As the Discover article notes, most of it sounds unlike what we're used to hearing; to me it's a lot like Hearts of Space "space music". Pretty cool in any case.