Here's a good source for everything you ever wanted to know about drive in theaters, including those that are still operational where they're located.

http://www.driveintheater.com/index.htm

The loss of the drive in has fundamentally changed American life. Try sparking a joint or go for some heavy petting with your date in the local Cineplex and see how far that gets you.
_________________________
I'd rather be ignorant than stupid. Ignorance implies a lack of knowledge which is easily correctable through education. Stupidity implies an inability to learn. Therefore; ignorance is temporary, stupidity is forever!