What was your favorite group/teamwork situation?

I hope I can explain this properly. I’m trying to see if different people like to interact in groups in pretty much the same way, or if there is some kind of divergence in preference. I’m thinking of groups in all kinds of settings: work, sports, social, religious, and whatever. Maybe if you think about your life, and when you had the most fun with a group of people, you could use that. Try to describe what the group was like: what is was for, how it got together, and most importantly, what unstated rules of behavior it developed, and how those came into existence.