I recently went to my 40th HS reunion. I hadn't been since the 10th but in the past 7 or 8 years actually got reconnected with quite a few people on FB - some that I wasn't all the close to in school. But having that base of interaction and knowledge about them meant that it wasn't like going cold into an awkward environment. Plus, we're all old enough now to be pretty over the cliques and such, and it was actually a whole lot of fun. We talked about how we've got to do it again before the 50th.