compressed air car - you could compress the air at your house using an air compressor,fill a compressed air tank in the car, and the car could run oof of it.you could use an engine very similar to a steam engine(using pressurized air instead of pressurized steam) to convert the compressed air torotational energy. the main problem woyld have is the size of 'gas tank' you would be get any type of resonable range.You would need a LOT of compressed air to take a car very far. an alternative would be use a liquefied nitrogen