CoolChange has a little project he's looking for ideas on. I posted mine. Go check it out and offer some thoughts.
I've re-purposed all kinds of things in my career, door hardware combined with micro-switches and Ipe wood keys to make "pianos" that play water features, floor drain grates Kynar finished to make refrigerant exhaust vents, you name it. One of my favorite things to surf on the web is real life hacks. If you've never done so, google search "real life hacks" and go read.