I tried out a "waterfall" contraption once--a small pop bottle filled with water that provided a pretty strong hit.
Others include a tin foil pipe (stupid!), a gold pipe made out of two industrial-type butt joint/screw/pipe thingies (also stupid), an apple, a Native American peace pipe, a bong made out of an alien-shaped cup from a carnival, hot knives, and the classic "pop can" pipe.
I'd never smoke out of anything made of aluminum, copper, or any other heavy metal now that I know better, btw.