Kevin,
Years ago there was an annual gathering, but by the time I realized it was local it had stopped happening. Someone hosted a small gathering in Saint Paul two or three years ago that I attended, but I haven't heard of anything since. There are quite a few members around the metro, but I guess Minnesotans are not terribly sociable.
I can't offer advice on HPM 100s, but I do own a pair of HPM 40s that I've never much cared for.