Ok, I'm fully prepared to get shot down over this one, because I know its a complete gimmick, but the idea did cross my mind, so I'm gonna put it out there.
In the run up to an event (for example the meet this weekend), could a countdown timer be put in the put on the forum index page or somewhere else?
I know it's like something you'd see on Bebo (not a fan of those kind of sites which is part of the reason I'm embarrased suggesting this), but it would draw attention to these events, and be a gentle reminder in the lead up to them.