HTML5 Genetic Algorithm 2D Car Thingy
The program uses a simple genetic algorithm to evolve random two-wheeled shapes into cars over generations. This is originally from http://rednuht.org/test/simulator/ - I just added legs, more wheels and different tracks (and removed the ghost/best car, because it was harder to update with those additions).
Check that page for more info, or this one (rednuht.org/genetic_cars_2/) for a newer version of their simulator, both loosely based on BoxCar2D.
(thanks rednuht for letting me make this version public)