The main task is to mount the projector to the ceiling, but there are other things to do as well. We'll stick with things that can be done within the air conditioned envelope.
Even if you cannot help out for the entire event, come for as long as you can. Drink some coffee (iced?), socialize, accomplish something, and have fun doing it!
Work Parties are always fun. Come on out and help our fellow Humanists to improve our home. We don't actually work that hard, and participants get a feeling of satisfaction, enjoying the improvements all the more.