GOPS is a simple bidding/bluffing game played with an ordinary pack of cards, with all the hearts removed.
One player takes all the spade cards, and the other all the clubs. The diamonds are shuffled and placed face down in the center of the table.
The diamond cards are turned over one by one. The players simultaneously bid for each diamond card with one of the cards in their hand (Aces low), and the player who bid highest takes the diamond card. If there is a draw, the next diamond card is turned over and the players bid again, the winner taking both the new diamond card and the one from the previous bid. If the final bid(s) end in a draw, neither player takes the last card(s).
When all cards have been played, the players count the value of the diamonds they have won. The Ace scores 1, Jack 11, Queen 12, and King 13, while the number cards score their face value. Whichever player has the most points wins.