We have a drive-in in a town about an hour north that has been there forever. Over the years, it became the "last one standing" and has become so popular (that and its huge restaurant-style snackbar,) that the owners opened a brand new one in the town where I live. Both places are pretty retro - about the only difference from the old days is FM sound instead of post speakers on wires.

Oh, and they're about $3 cheaper to see opening weekend movies.