Two meetups I can remember didn't have enough people at them to make them what they could have been. By the power of disjunction, I bet that one of them was only scantily attended because people couldn't make it that week, even though it is a worthwhile topic.

So, two topics for this meetup: Nomic (A game where you vote to change any of the rules) and Folk Wisdom (How to extract real wisdom from it),