Anyone else here ever play a card game called Mao? It's an interesting game. Usually only the dealer knows the rules, and the players have to figure them out as they go. There's two versions. The easy version, in which you're told what rule you're breaking when you break it, and the hard version, where you have to figure it out on your own. In the hard version, you're not even told that you're being given a card for breaking a rule.
It's been ages since I played, but it came to mind recently.