My high school class had one reunion so far, but I was out of the country when it happened. From what I heard, the turnout wasn't great, so I will likely only go to the next one if I happen to be in the area (as it seems unlikely it will be worth traveling) and if I am sure of at least a few people I know/knew attending.
"History is the road map and without it there is no way to navigate the future." - George Wunderlich