While at Comic Con Angela and I made friends with the folks who run a Trek Costume Club called the USS Navras. They have members all over the world and they, like the Star Wars costume club "The 501st", attend charity events and make appearances at various events.
I'm considering joining them...looks like they need a "Sevryll". Thought I'd share a link to their site. If you like costuming, or just fan clubs in general (no costume required) you should check them out. They're very cool.
http://ussnavras.com/ (http://ussnavras.com/)