When I was younger, I was a card carrying AMA (Academe of Model Aeronautics) member. I took a short break from the hobby, and when I got back into it, park flyers were everywhere making it possible to fly almost anywhere. At the time I didn't see the need to join the AMA, as I wasn't flying at a club.
Recently this has all changed, first of all the AMA realized that they could create a new membership tier that is aimed at people who fly small aircraft. The Park Pilot program offers a cheaper membership to the AMA with a few limitations. Clubs can choose to allow you to join with the PP card, or they can deny you membership till you have a full AMA membership. A weight restriction of 2 lbs and a top speed of 60 mph, has been set on PP models.
After much contemplation, I decided to join the Park Pilot program and see what it offered for me. One thing I've enjoyed is the quarterly Park Pilot Magazine. It is full of insightful reviews, aircraft plans, and new product information, all aimed at small electric aircraft. Additionally, I have been able to see other Park Pilot members in my area (currently very few). At some point I would like to try and start a club for electric flight, aimed at indoor flying in the winter and park flying in the summer months.
Check out http://www.theparkpilot.org/ for more information.