Pub Theology - How's it done?

I'm beginning a summer series of down-to-earth faith & life conversations in homes (or backyards, decks, etc.) this summer.  Though I already have a bit of a plan, I'm wondering how those "Theology on Tap" or "Coffee House Theology" events are structured.  If you've ever led or attended such an event, please share your thoughts and insights here.  Thanks!