It's been posted elsewhere on LW before, but here's a brief meetup summary + attendance of the DC metro area group, for approximately one year now. We hold weekly meetups, typically in a museum courtyard, and seldomly at people's homes. Attendance varies, but the average is around 10. Frequent meetup activities include, in no particular order: structured activities, suggested-topic discussion, games+social meetups, and lesson-type activities led by one person on an area of expertise.
In addition to the actual meetups, we've had a weekly role-playing group (drawn from the same pool as meetup regulars) since Spring 2013, and we occasionally organize "extracurricular" group activities including but not limited to mega-meetup travel. Typically, group events snowball from someone mentioning something and people expressing interest, Doodle polling happens and we decide on a date and other details. It helps that we have people willing to be leaders by fiat, to move things along.
Because of the RPG being held before the meetups, and more often than not, eating out and post-dinner social/hanging out, our meetups may informally last for 8+ hours, although people often leave early, or before or after dinner.
I can try to go into detail on specific meetups or activities, if people have questions.
If you had an interesting Less Wrong meetup recently, but don't have the time to write up a big report to post to Discussion, feel free to write a comment here. Even if it's just a couple lines about what you did and how people felt about it, it might encourage some people to attend meetups or start meetups in their area.
If you have the time, you can also describe what types of exercises you did, what worked and what didn't. This could help inspire meetups to try new things and improve themselves in various ways.
If you're inspired by what's posted below and want to organize a meetup, check out this page for some resources to get started! You can also check FrankAdamek's weekly post on meetups for the week.
Tell us about your meetup!