The most productive discussion so far has been about Thinking Fast and Slow. Our de facto guy-in-charge put an overview on a whiteboard and linked to some LW posts about the book beforehand, so I was able to follow the conversation despite not having read the book. But it's too early to really tell what's working and what's just the excitement of a new group starting up.

The purpose of the meetups I hope is to a) meet sane people who can become good friends, b) push each other to become better thinkers, and c) coordinate projects. Building community is good for a. and b., b. and c. are good for practice and learning.

I would note that passing around a textbook does not appear to be that great a method of group study. Probably would work better to assign someone to do a presentation on a chapter or two and then pass it to the next guy.