Guerrilla drive-ins come in two flavors: a true drive-in, or a walk-in. Walk-ins were the first guerrilla movie method, and involve a big grassy area, some blankets, and a movie projected on a screen. The projectionist powers the projector using a generator, and big speakers are used to project the sound. A true guerrilla "drive-in" is just that - a bunch of cars and a movie. The projectionist usually powers the projector with his or her car or a small generator and an FM transmitter transmits the soundtrack to the other cars. The Mobile Movie (http:/www.mobmov.org) was the first guerrilla drive-in.