I am loathe to just pinch articles from boingboing but I'm afraid I had no choice but to make sure you all knew about The Cat Piano.
Yes, it's exactly what you think: the keyboard is connected to a mechanism that jabs a sharp spike into the bum of the appropriate cat, each of whom has been selected for the pitch and tone of its meow. Oh the cruel mirth.
I am obliged to recount that the brother of a certain reader of this blog has a variation of this instrument, called The Cat Bagpipes, in which the cat is held splayed in the arms in a manner that resembles bagpipes. The cat's tail is held in the mouth and upon the 'player' biting it, the cat then utters sounds not unlike the tones of a bagpipe.
Now before I get spammed by animal rights activists, I just want to say I don't condone this behaviour.
But it sure is funny.