The only other forum I participate with any regularity is the Vanguard diehards. We recently formed a group, and have had 2 meetings. Right now we are meeting once a quarter. Everything is very informal. There are no dues, commitments, etc. We meet in a public cafe, so folks do not have to fear any internet predators, etc. on a Saturday afternoon. The cafe is in a business district, so it is pretty empty on a weekend. We take over about half the place, and since they only have counter service, folks can get up and buy what they want without any obligation and bring it back to their table. We meet for a few hours and try to have a list of topics in advance that are solicited from the attendees. We drew about 30 diehards/friends at the last meeting. Right now there is no official attendee list, so people can still be fairly anonymous. The organizer has the email addresses of the folks who were interested and contacted him, and he sends out a group email with a list of dates before each meeting to try to come up with a date that would work for most of us.
What is nice about this format is that it is easy to get up and move around. Midway through we switch seats so everyone can meet others and get different perspectives. The group is too large for one big circle. While this group takes more of an investment slant, and sticks to that, I bet our discussions here would be more far ranging.
I am also in the Garden State and would definitely welcome starting something up. I had thought of mentioning something here but did not think we would have critical mass. BUM, my suggestion is that for now to keep it simple. All we really need is to choose a date and location, and ask anyone who is interested to email the organizer, who would then privately send the details to the responders. One other suggestion is to find a place within walking distance of a NJ train or bus line, in case we get any folks from NYC. About half the diehards group take mass transit to the meeting from the city.
If there is interest, I could scout around for a location. There are many places that would love a large group meeting on a Saturday afternoon (even a bunch of potentially frugal RE types).