Go Karts!
Not the super low and fast death traps.. I mean something like this: http://www.diygokarts.com/imag…ns-kart/kart-done-700.jpg
Maybe it's the first form of motorized vehicle that can be made?
If you get stuck.. just get out and move it by hand.
Yank on a rope or cable with a handle to get it started. If you don't keep it in good shape, it will become more and more difficult to get started etc...
Would be great fun!