One of the more interesting games I've seen is coöperative poker solitaire. In poker solitaire, you are dealt 25 cards and lay them out in a 5x5 grid. You try t

One of the more interesting games I've seen is coöperative poker solitaire. In poker solitaire, you are dealt 25 cards and lay them out in a 5x5 grid. You try to make the best possible poker hands. The general scoring works by trying to make the bets possible hands working down from a royal flush. So if you have the cards for a royal flush, you have to make that. If you have the cards for a lesser straight flush in the same suit but can't make the royal flush, you don't have to make the lesser straight flush. Anyhow, the really interesting game is a coöperative two player variant. Thirteen cards are dealt to one player, twelve to another. Players cannot see each other's cards. The player with thirteen places a card on the table, then turns alternate. Once played, cards cannot be moved. At the conclusion of the game, the cards must be arranged in a 5x5 grid. So technically the first two cards could have three blank spaces between them diagonally, horizontally, or vertically. Pairs cannot communicate via any means other than the cards they choose to play. So to play well, pairs generally work out a system for signaling what they have, i.e. opening with a strong card and so forth.