Neonchameleon
Legend
I thought I'd also expand on something. My current gaming club, The RP Haven thrives based on short campaigns (four quarter-long campaigns a year). We're only fifteen years old, and up to eleven branches (not counting the online branch) and happy to help set up more.
The short campaign model lets the RP Havens avoid both the common problems of D&D clubs that don't just collapse. The first is that very shortly you'll end up with a club that's basically two or three home groups, six months or more deep into a campaign that just happen to play at a shared venue. Neither can take new players so the club can't take new members and the club is going to break as life happens to the two or three groups the same way home groups break. The second problem is that clubs that avoid this trap then basically run one shots which are fine but one shots miss a lot of the benefits of campaigns. Oh, and it makes for a much lower barrier to entry for new DMs.
The short campaign model lets the RP Havens avoid both the common problems of D&D clubs that don't just collapse. The first is that very shortly you'll end up with a club that's basically two or three home groups, six months or more deep into a campaign that just happen to play at a shared venue. Neither can take new players so the club can't take new members and the club is going to break as life happens to the two or three groups the same way home groups break. The second problem is that clubs that avoid this trap then basically run one shots which are fine but one shots miss a lot of the benefits of campaigns. Oh, and it makes for a much lower barrier to entry for new DMs.