The saw blade. I've heard once or twice someone take a hand saw, bend it, and make music. I can bend the blade and make a tone, but MUSIC? I could probably learn to make music, but even if I was the best saw blade player in the world, there isn't much a need, since it isn't a versital interment.
Pipe organ is another on my list, but there is some chance of that. If I can find the money I'm planing to build a house with on. (NOT an electric organ, a real pipe organ with real 8 foot pipes. Maybe even some 16 foot pipes. And the some seceret passages so that I can complete the ghost story.