The Silbervogel Gravity Car concept, by Jakob Hirzel from the Pforzheim University Of Applied Sciences in Germany, has no engine, but still wants to grow up and be a real racing vehicle. The racer relies solely on, you guessed it, gravity to pick up speed. We're thinking the whole exempt engine thing is going to give the Gravity Car a little handicap in conventional races, but as a play thing, it would be pretty great. [Jakob Hirzel via Tuvie]