Asklemmy

There's a variant of the card game War called Spoils of War, or Sow, that adds some strategy:

There can be up to five cards max in a player's reserves. These cards can be pulled out in any battle and added to the player's fighting card. Opponants have to option to do the same, and the original player can respond. This continues until all players can't or won't add any more and the highest total wins.

Aces beat all face cards but lose to all number cards. In a reserve battle, aces count for eleven.

In any regular battle, any player can choose to sacrifice two facedown cards to place the fighting card into her reserves. The sacrificed cards go to the winner of that battle. If all players do this, the sacrificed cards are claimed by the winner of the next battle.

If the two highest fighting cards in are tied (a "war" in the original game), or there's a three-way circle of Ace beats Face beats Number beats Ace, or the totals in a reserve battle are tied, those players must place five face-down cards for the winner of the next battle to claim. Only those involved in the stand-off play the next battle.

The winning player of each battle may place all cards taken in that battle at the bottom of her deck in whatever order she chooses.

Overall, it adds a bit of strategic depth while still keeping a small footprint in tablespace and setup time.