When I was in school I watched a friend make a small V8 engine where the pistons moved up and down, turned the crank with an air hose hooked up. It never occured to me till now that this is such a genuine alternative. I'm not worried about oil anymore. If I have to, I'll make my own air powered engine.
Production cars that run on compressed air are going into production:
The CityCat model will clock out at 68 mph with a driving range of 125 miles. That should work fine for just getting around the block and use no gas.
http://green.yahoo.com/blog/ecogeek/...roduction.html