One thing that seems to work for us is to have an incentive for membership sign-up. We give eacher member a school telephone directory and a few other things. Another thing that we do is a grade/class competition. Winning class in each grade gets free ice cream one day. The first class to get 100% participation gets a pizza party. The principal also encourages teacher membership. The first grade for all teachers to become a member has a free jeans day.
Those are just a few ideas. I represent a large school in a large district in Texas. Our elementary school has 1300 students. I know things are a little different up North.
Another thing that we did when we were a smaller school-We made a paper tree for each grade and cut out apples. As parents joined, we wrote their child's name on an apple and put it on the appropriate tree. The first tree full got a pizza party.
I've got all kind of neat ideas. Been doing this a loooonnnnggggg time. If you want an example of the form we are using this year, please e-mail me with your info. and i'll send it as an attachment.
I have a lot of ideas that worked as far as getting people to come to meetings. But, I think my post is entirely too long. Let me know if you are interested in a few of these ideas.