The Portland Bike Ensemble plays free improvised music
on amplified bicycles.
Here's an mp3: Polyp & Fury Quintet (2:48)
For more about the Portland Bike Ensemble or to purchase one of their limited run of 500 individually designed one-of-a-kind sleeve vinyl releases, visit the Portland Bike Ensemble site.
For another recording on a cd in a tin case with a piezo electric pick-up and instructions so you can play your bicycle as a free improv instrument, follow this link to Jyrk Records and look for catalog number JYRK_16.