What kinds of things do you guys do to market or promote your forums? Over the years, we've put together promotional materials that have been given away at events and in our case, in stores. We've had small gatherings of members and moderators and we've attended launch events in NYC at which we've garnered further publicity. We've also done a few press releases (boo!), and had minimal coverage in national and international newspapers.
I'll attach a sample of the card we put together last summer - 2000 down, 4000 to go! These were done as 4"x6" double-sided glossy postcards for an event, and we've used them as our promo cards since.