I'll add "the local library" to that list, as well. A good one often has programs for elementary students and teens as well as the early literacy programs aimed at preschoolers and infants. Ours has been a terrific resource at times.
If you have a local university/college, activities sponsored by the institution may well concentrate faculty kids (local peers), and at least draw in kids whose parents are actively looking for enrichment with the local uni/college.
People with terminal degrees tend to have GT kids; this makes complete sense when you think about it.
Anyway, that is another place to find a better, higher-skewing mix of peers.
