I've heard a lot about LessWrong meetups and how everyone seems to really enjoy going to them, but I'm not actually sure what happens there. With COVID-19 abound, I don't intend to go any time soon, but I'm interested in going at some point in the future. What sort of events would happen at these meetups? In particular, information about the St. Louis meetup would be best.
You could try messaging the St. Louis organizers. I think meetups tend to vary a fair bit from city to city.
The meetups we've run in SF and DC in the past were mostly low-key, with some group activities like "help other people with their life problems," sharing and discussing interesting articles, and board games. (There's a pretty exhaustive list of our formats here: https://tigrennatenn.neocities.org/meetup_cookbook.html)
Other organizers sometimes have higher production value, bringing in outside speakers, or focusing more on rationality content (e.g. "let's go through a recent CFAR handbook one activity at a time"). Or they might be even more low-key, just hosting social meetups with no topic at a cafe. It really depends.