you can pay out arbitrary bonuses once they've answered. so you could easily do single-round prisoner's dilemma, and have amazon pair up 2 (different) folks at

you can pay out arbitrary bonuses once they've answered. so you could easily do single-round prisoner's dilemma, and have amazon pair up 2 (different) folks at a time, and when you get the results back, look to see what the folks in each pair did, and award bonuses appropriately. i'm not sure if there is a way to do an iterated version.