"The Super Awesome Micro Project", as this has become known, is not a special effect. That really is a life-size car made out of LEGO, and it really is being powered by an engine made out of LEGO.
Built from 500,000 bricks, the engine (four orbital engines with a total of 256 pistons) uses compressed air to propel the car. OK, so it won't hit the speeds you'd get from a real hot rod (it tops out at 20-30km/h), but a real hot rod can't match this for fuel economy or awesomeness, either.
It was built by a Romanian kid and an Australian entrepreneur, and is currently turning heads in Melbourne.
Life Size Lego Car Powered by Air [YouTube]