This is cool as hell. Check it out and sign up:

Definition of a Mobile Movie
A "mobile movie" or mobmov for short, is quite simply a drive-in that drives-in. Participating in a mobmov is very similar to attending a drive-in from the days of old, except now the projector is located inside and powered by a car, and the audio is piped in stereo over the FM band to your car. It's a new technological twist to a nostalgic idea.

How do I participate in a MobMov?
Simple. Sign up to our mailing list. Showings will be held at various locations all around the Los Angeles area. The day before each Mob, we'll e-mail everyone with the location and the movie. If you want to join in, all you have to do is fill your car with your friends and find the spot. Go to their site and their blog.