The Lego Lynton cliff railway. This is based on the real Lynton-Lynmouth cliff railway in Devon. Mine is about 4ft tall and made completely from lego. It works on marbles, rather than water (water got too messy - I tried it).
In honour of the real cliff railway, this now has its own webpage: Legoton Cliff Railway and a movie of the cars in motion
The lego etcha sketch. This was originally designed for use with a formal modelling program, for comparison to a purely virtual etcha-sketch. It is fully working, with the pencil able to travel to any point on the paper automatically. Control is via the Lego Mindstorms RCX.
Bart's sliding puzzle
