Some of the meetups are just kind of generally social groups, which might be a good start for you. I was just looking at Boston and holy cow, there are a lot of groups!!
I know you have some DBers that are in your area, too. I can't remember who, but there was a get together in Boston last year. You might look through the Just For Fun section and see if you can locate any of them (or I'll do that if I have time later, but have a pretty hectic week coming up).
As for meetup - here are some links that might get you started. You might want to set up an email address just for meetup stuff, if you can. You can end up getting a lot of email from there.
You'll have to register before you can get to the details of any of the groups, so I'd do that first here: http://www.meetup.com/register/
Then take a look at these:
Newest and Largest groups: http://www.meetup.com/cities/us/ma/boston/newest/ Bigger isn't necessarily better (don't we all know THAT!) - but a lot of times the bigger groups are also the most active, so this is a good place to look. Newest can be fun to get in a group from the "ground up" - but a lot of them fizzle out, too, so I'd start with an established one.
30 and 40 Something's Social Networking http://socialnetwork.meetup.com/422/ and here's their calendar: http://socialnetwork.meetup.com/422/calendar/ Started out as a singles group but is now just a "go out and have fun" group - says specifically it's NOT a dating thing. Looks like they are very highly rated by the members. I'd definitely try this one out! You can click on any of the events to get more information about it, see who's signed up, etc.
Night Life (if you're into the club thing at all) http://nightlife.meetup.com/29/ They have a new member one this weekend - lounging and Tapas... looks fun!
Girls' night out: http://nightlife.meetup.com/138/ Looks like they have a good variety. This one's "private" so you'll have to drop the organizer a note before you can sign up.
Sep/D. Support: http://divorcesupport.meetup.com/249/ .. if you're ready. If not, hold onto this one for later. Looks like they do a lot of social type events too, so that might be fun.
I forgot to mention - don't be afraid to hit the "sign up for this meetup" button! It doesn't commit you to an event, it just puts you on the list for that particular group, and lets you see their message boards, photos, etc. It can help you get a feel for a group before signing up for anything. You aren't signed up for a specific event until you go to the calendar and RSVP Yes.
Once you get more specific on your interests you can look those up too, but this should be a good start I hope.
Me 35, H 38; Together 13.5 yrs, M 7 Bomb 1 10/07/06 Sep'd 1/14/07 - 4/15 Piecing: 4/07 - 9/07 Bomb 3 10/11/07: Never loved you, let's separate 2/08 slowly improving 7/08 Piecing (7/25/08 rings back on!!) Current thread