I find it much easier to talk to parents at the rink or soccer field (or something else) where DS is decidedly average. It is much less threatening for parents to bond over your kids being off in the corner picking dandelions rather than being the team super-star. It is also good for DS to have something other than astrophysics or prime numbers as common ground with his peers since we have yet to encounter another 7 year old that has any of his other interests. As a bonus it has made DS realize that some things take practice, not everything is easy and we've been able to use this when he is frustrated when kids in his class have to work at something that is easy to him.
ITA with ultramarina - some clubs/activities are more likely than others to find like minded kids. Not sure where you live but hopefully there are some options there as well.
