Original Card Games by David Parlett
Players 2   Cards 52   Type Tricks
I've always had a penchant for games in which a trick must contain exactly one card of each suit - see, for example, Addenda and Flashpoint. Here's another one.
Cards and deal
Deal 12 cards each and stack the rest face down.
Object
To win tricks, especially by playing two cards with the greatest possible difference between them. For this purpose cards have numerical values from Ace = 1 up to King=13. Thus if the cards you play are King-Ace the difference between them is 12 (=13-1), while if they are equal the difference is zero.
Play
Non-dealer leads to the first of 13 tricks. Each trick will contain four cards, one of each suit, of which the leader plays the first and third cards and the follower the second and fourth. At the end of a trick each player announces the difference between the two cards they have played, ranging from 12 to zero as described above. Whoever's two cards show the greater difference wins the trick and scores the difference between the two players' differences. For example, if North plays Q-5 (difference of 7) and South K-J (difference of 2) then North wins the trick and scores 5 (i.e. 7-2). If both show the same difference, giving a score of zero, the trick is won by the player of the second and fourth cards to compensate for having had fewer choices of suit.

After each trick you both draw two cards from the top of the stock so long as any remain (trick winner taking the first and third) to restore your hands to 12 cards, and the previous trick-winner leads to the next.
Duplicating a suit
Remember that each trick must contain exactly one card of each suit. If you play a card that matches a suit already played, you must take it back again and play from a different suit, and you automatically lose the trick regardless of its final total. If both players make this mistake in the same trick, it is lost (regardless of total) by the player who committed this fault last. With proper play, it should always be possible to play without matching a suit. In the rare event that one player cannot do so, play ceases immediately. Neither player wins the current trick, and the scores made up to that point are counted as the final score for that deal.
Score
You each score the total of differences you have made plus the number of tricks you have won. In case of a tie the winner of the last tricks adds 1 point more.
Game
A rubber is the best of three games.
Variation
If the leader plays the first and fourth cards instead of first and third, and the follower plays the second and third cards instead of the second and fourth, this will approximately even out both players' chances of being able to choose a suit to play from. If this rule is applied, and both player's differences are the same, the trick is won by whoever played the highest-ranking card, or, if still equal, by the person who played second and third. It would be interesting - but I haven't tried it - to add a rule that all four cards played to a trick must be of different ranks as well as different suits.