A motor powered Strandbeest made from K'nex!
Strandbeests, which means "beach beasts," are a type of kinetic sculpture made by Theo Jansen. These sculptures are able to walk with only wind power. After designing the walkers with a special algorithm, he races them on the beach to measure their fitness and incorporates the best traits to modify improve the design. The designs grow more complex over time, and have artificial stomachs, obstacle detection and other features. This video should give you an overview.
Here is a video of my Strandbeest. It has terrible traction on concrete, and the motor is a bit underpowered.