I'm in a book club with some members of a sister church. It's cool, because we have yet to read a Christian / inspirational selection. We meet once a month (or when life allows -- December was mad for us all) at a local coffee shop.
I have a difficult time finding book clubs in my area, I'd prefer a RL one since it would force me to become less reclusive and help me open up socially (right now I'm very much a small select group of people are my friends and the rest of the world may go disappear for all I notice, which isn't so good at my age).
Online I belong to an informal one we just started in the Study Buddies group on Goodreads (the group is based around Maria V. Snyder's book series Poison Study, Magic Study and Fire Study as well as the forthcoming sequel series Storm Glass).
I love book clubs. In fact, I've started an online book club that will open its 2nd discussion on Jan. 12th. We have three books selected for discussion this round. The name of the club is "LOST IN A GOOD BOOK."
I'm in a book club with a Jewish theme; we read both fiction ( The Yiddish Policemen's Union, Everything is Illuminated, etc.) as well as non-fiction (Maimonides bio, for example). I admit, we do spend a lot of time eating and drinking, but there usually are some solid minutes devoted to the book. Next up: The Man in the White Sharkskin Suit, which seems simsilar to our last one, My Father's Paradise.
I've never tried an on-line club, but may set one up this year on the Read Street blog.