I'm not exactly sure if this should be under Math or Behavior, but I'll try here first.
I was just reading the wiki article on the Centipede Game and I thought of another, similar game and I was wondering if there's a name for it (so I can go look it up).
Anyway, the idea is, instead of adding outside money to the piles as they are passed, do this instead. Start with 50 coins in each pile, and when the piles are passed, one coin is moved from the smaller to the larger.