During the 50s and 60s drive-in movie theaters were a popular American staple. While most of today's generation won't be familiar with them, you can recreate the fun for your next fundraising event. An exact replica might be out of the question, but there are different ways of reproducing the same feel.
One way is to locate a large building with a smooth surface that's suitable for projecting a movie on to. If you want to get really elaborate, you can rent a local radio frequency that enables you to broadcast the soundtrack for people to listen to in their cars.
A more straightforward approach is to have your “drive-in” movie showing inside a gym or cafeteria. Project the movie on a screen and have the audience sitting on lawn chairs or under blankets instead of in their cars.
Charge a suitable entry fee for people to come in and watch your movie and have a concession stand available to raise some extra funds as well. It might be a good idea to display a countdown for the start of the movie so that everyone knows how much time they have to buy snacks (you could see if you can track down the corny dancing snack movie that used to play at old drive-ins). This is sure to be a fun event for everyone involved.
For more information on drive-in movies and other movie fundraisers see our in depth article on the topic.