On the topic of playing the piano in strange ways, if you haven't heard John Cage's Bacchanale, you must!
http://www.youtube.com/watch?v=i0BwwF9cLwM

It's written for "prepared piano". In Cage's use, the preparations are typically nuts, bolts and pieces of rubber to be lodged between and entwined around the strings. Some preparations make duller, more percussive sounds than usual, while others create sonorous bell-like tones. Additionally, the individual parts of a preparation like a nut loosely screwed onto a bolt will vibrate themselves, adding their own unique sound. By placing the preparation between two of the strings on a note which has three strings assigned to it, it is possible to change the timbre of that note by depressing the soft pedal on the piano, which moves the hammers so they strike only two strings instead of all three (the soft pedal is traditionally called "una corda" on a grand)."

-J