Missed this thread before, so just adding my method here, looking foreward to trying some of the other methods too, anyway here's a vid I did.
http://www.youtube.com/watch?v=cVRp7e6GQS4Description on the video gives a rundown how to do it, I did not spend too much time refining it but anyway it gives you an idea. I ran into a few different and interesting sounds such as plucked string, tabla type sounds and some nice FM sounding percussive stuff. More a proof of concept than anything