Algodoo

a and d to move snowboarder. go in the fences and avoid the obstacles. (going in fence not neccesary, but it makes the red lights turn green(which is a much more awsome color then red) but hit the obstacles, then...)
there is a difficulty setting, that is the sim speed. There is a customization system, to make ur own level, delete the current obstacles, then, copy paste the fence/obstacle on where u want it to be. (no need to fixate it... jus don`t)
and enjoy!!