Hey BikeChick! I don't feel my responses can equate to those already posted because I live in a very rural area and there are only a few of us who ride regularly (road bikes, that is). However, there are several very active larger clubs in the area who have much larger memberships.
Our club is loosely organized & we communicate through a yahoo group site. According to the site we have 42 members +/-, though we usually have an average of 5 show up for a ride - sometimes 10+, mostly not. Like I said, we're out in the boonies of VA
I didn't join the group - the group sort of evolved around us. We found out through happenstance that there were a number of us living in the area who all loved road riding & we started riding together. The rest kind of "happened". We help sponsor the only large fund-raiser ride in our county each year. This coming year is the 22nd or 23rd year and it continues to be one of the more popular in the region, simply because of the location - roads, scenery, etc. The proceeds benefit the local recreation department.
Tulip had some great comments & RABA is an awesome club. Much bigger than anything we locally will ever have. Best of luck to you!
"When I'm on my bike I forget about things like age. I just have fun." Kathy Sessler
2006 Independent Fabrication Custom Ti Crown Jewel (Road, though she has been known to go just about anywhere)/Specialized Jett