yeah man , go for it! Movie under the stars .. romantic stuff and will definetly score points with your girlfriend.
But go early and get a seat in the middle .. other wise u going to be sitting at the side / front or back .. which can be a pretty big strain on your neck ( thus not scoring points ) however .. don't sit near the projector as its freaking noisy .
Also bring a ground sheet n pillows , titbits and drinks. Win already.
OT, i once saw a group of people bring a pot of curry in.. so they dipped it with bread and brought satay sia ... oooo its making me hungry already.