Busted Bricks is selling a laser-cut Marble Machine kit for £12.95. It can be assembled for either left- or right-handed use.
The worlds (sic) first commercially available minature (sic) hand-cranked marble machine with both lifter and track cut on a laser. The #1 kit is an easy to assemble marble machine that will look great on any desk, bookcase or on a plinth in the British Museum. Cranking for a few minutes daily is a great way to relieve stress and improve your fitness level (OK, the last claim might be a bit optimistic but isn't that what advertising is all about?). The motion is geared to efforlessly (sic) lift the 5mm steel balls to a dizzying height from where they will start their journey down the track at break-neck speed. If steel balls could speak I'm sure they would go: "Wheeeeeeee!!"
Marble Machine Kit #1 (Thanks, Graham!)