Because riding while wearing headphones can be dangerous, Hammacher Schlemmer is offering an MP3 boombox for your bike. It snaps on to any 1" frame and plays back 1GB worth of music (an SD slot allows for expansion). The casing is weather resistance and charging is handled through USB...since you can always charge USB on the trail.
Technically, the MP3 player can be completely removed from its docking station to be used without the bike, but that sort of ruins the point of not just purchasing a better MP3 player for less money. I think this thing is hideous - eerily reminding me of those huge radio headphones that for some reason only come in fluorescent yellow. It can sync with PCs and Macs, but only if you want to put your computer through the humiliation.