Our school district also has an organization. They also have speakers a couple times per year. Mostly they keep people updated with a listserv that lets them know about speakers, political action and other topics related to gifted education in our area. Last year when the district was looking to save money by uprooting successful gt programs, the gt parent organization galvanized a letter writing campaign that appeared successful (no programs moved). They also have been disseminating information about some ballot initiatives that would decimate K-12 funding in our state.
I've heard that the non-speaker meetings tend to attract the negative people (i.e. people who want to complain that the district isn't doing what they want for their kid.) I haven't attended because they are at an inconvenient time.