Puzzle box. These are a lot of fun to make. three hours on the band saw (and three months sanding & polishing). It's all freehand -- no measurements to make, just a rough plan to follow. Get yourself a bandsaw and a 1/16" blade and make your own!
Telescope. 10-inch Dobsonian reflector. Optics tested to 1/10th wave accuracy. Hand-made from birch and pyrex. For more pictures, and a description, see Miatascope.