"Skull" or "Skull and Roses" is a table top game. The rules can be found here.
I was thinking of how I could play this game P2P. At first it seemed easy: Each time I had to place a card face down I would make a choice hash it, send it to my opponent, and then when it needed to be checked you could give out your answer and it could be verified by hashing it. The problem is that without all players revealing all of their card at the end of a round, there is no way to verify that someone didn't put down more than one skull, or put down more roses than they had. This problem seems like a simplified version of mental poker to me, so I am hoping someone with more knowledge on the subject would know how to play this game without a trusted third party.
In case the link provided goes dead here is a synopsis of the rules: Each player gets a hand of 4 cards: 3 rose cards and 1 skull card. At the start of each hand each player places one card from their hand face down. Next players take turn place another card from their hand face down on top of their previously placed cards. When it is your turn instead of placing another card face down you are also allowed to "challenge". To challenge you announce a number of less than or equal to the number of cards placed down. You now enter a new phase of the game where players take turns naming larger and larger numbers until someone either decides to "pass" (not naming a larger number), or someone names a number equal to the number of face down cards. When the "challenge" phase is over the last player to call a number has to flip over that many cards. If the player flips over a skull he has to discard a rose card for the rest of the game, however if he does not flip over a skull card, he gets a point. Everyone now collects the cards they played face down, and a new round begins. First player to two points wins.