I started working with generative music quite a few years ago, when I provided scores for the later Creatures games. As the games ran continuously with no narrative, there was an advantage to having a random ambient background rather than a continuously repeating composition. I wrote a brief article on it here, although it's rather weirdly been shifted into third person.
This website features a number of generative pieces. These employ a similar approach to the tape loop experiments by Brian Eno on his 'ambient' series. Instead of tape loops, they use several instances of a flash media player, each with a different playlist. The playlists all are different lengths with silences scattered throughout, and so the pieces are essentially infinite. Due to random loading times, it's unlikely to even be the same on two different machines. I've always wanted to write more generative pieces, but they're not easy to distribute. This player provided a simple solution!
As the pages are running several players in parallel, they may not work on older machines or low bandwidth connections. Or maybe there will just be more spaces between the notes...