There are upcoming irregularly scheduled Less Wrong meetups in:
Cities with regularly scheduled meetups: New York, Berkeley, Mountain View, Cambridge, MA, Toronto, Seattle, San Francisco, Irvine.
If you'd like to talk with other LW-ers face to face, and there is no meetup in your area, consider starting your own meetup; it's easy (more resources here). Check one out, stretch your rationality skills, and have fun!
If you missed the deadline and wish to have your meetup featured, my username is dreamalgebra on google's webmail service.
To reduce front page clutter, the new plan is for meetups to be initially posted in the Discussion section, and for Anna Salamon to make a promoted post "upcoming meetups" post every Friday that links to every meet-up that has been planned for the next two weeks. [HT: Carl Shulman.] Please let her know if your meetup is omitted. (I'm filling in for Anna this week.)
Please note that for your meetup to appear in the weekly meetups feature, you need to post about your meetup before the Friday before your meetup!
If you check Less Wrong irregularly, consider subscribing to one or more city-specific mailing list in order to be notified when an irregular meetup is happening: London, Chicago, Southern California (Los Angeles/Orange County area), St. Louis, Ottawa, Helsinki, Melbourne.
These posts should probably have a new tag, like meetup_summary.
Edit: Assigned the tag.
The Ottawa Bayes study group is actually a chapter of the Bayesian Conspiracy. We just don't publicize that fact because, well, it's a conspiracy.
There's an upcoming Toronto meetup on May 24th that didn't make the list.
I'd be quite keen on setting up a LW meetup in my area (Birmingham, UK), but haven't actually seen any evidence that there are other LW readers anywhere near me.
Just make a discussion section post about it.