I'm not really a guest, I'm just here on a computer that isn't mine and doesn't have a cookie. Oh, well.I know a guy who builds his own kooky instruments. He has a folding guitar (yes, with hinges right in the middle of the box--you take the strings off and fold it in half for extended travel). He's also a great musician.
My strangest hobby is model horses. I can make functional saddles, bridles, and harness for four-inch plastic horses. I also cut pieces off, then reattach them, resculpt the muscles, and repaint them. I know it sounds like a big loser hobby but I can talk equine conformation and color genetics so well that "real-horse" people can't tell I'm not one of them. I probably should have been a dentist--I work very well in small scale.