Have you ever sat down and listened to computer music? Not music created on a computer, but music created by a computer? Probably not, huh? There's good reason for this - computers can easily handle the mathematical rules of music, but arranging said rules into a coherent and enjoyable song is another ballgame entirely. This is why software like Brian Eno's Koan Pro veers away from the rigid structure found in today's popular music in favor of a more Zen-inspired sonic environment. Sure, hits by the Spice Girls and Hanson may seem like they were written by machines, but chances are there was at least some human (or possibly alien) intelligence behind the curtain, calling the shots.
That said, I've gone and created my own bit of pseudo-generative music "software" for Microsoft Internet Explorer 4.0. Of course, it's pretty simple compared to some of the stand-alone packages, and yes, its output lacks a certain aesthetic je ne sais quoi, but occasionally there are flashes of brilliance for which I would gladly claim authorship. And, seeing as it will continue to play until you or your machine cries mercy, it can at least be called prolific if nothing else.
Software: Internet Explorer 4.0.
Got the tools? Get the demo.