I have to give props to a guy that I've seen at a few of SF's Sunday Streets (there are only four left this summer, so no more slacking, slackers!).  In my opinion, this is the coolest bike I've ever seen -- way better than the conference bike or even Deep's FlashDance bike.  Sure enough, that's a real acoustic piano mounted on the reverse tricycle frame, complete with hammers and strings and everything.  Sound is decent, and remarkably loud.  The bike is steered by applying forward pressure with either your left or right hands.  I think it has an old skool braking mechanism where you pedal backwards to slow down.  I would love to ride that thing down some of my favorite hills like Clipper or 17th street!  My guess is that the odds are very low that he will let me borrow it for such a purpose. :^)  The crash would probably sound really cool.