Schafkopf

Traditional German card game played with a Bavarian 32 card deck. Similar to Skat but simpler bidding and scoring rules. Can also be played with a traditional French-suited 52 card deck by removing the 2-6 of each suit.

Players either play in teams ("I'll play with the Ace of Leaves"), or one player decides to play a solo (worth more points) against the other 3 players.

Typically played for money.

Sheepshead

The Americanized version is known as Sheepshead. This is one of the few traditional card games with a hidden partner. There are two well known variants with devotees of each.

Jack of Diamonds is a random partner method where the picker receives a partner without needing to call or lead a suit. The picker can still choose to "go it alone", but needs to declare before the hand begins.

In Called Ace, the picker calls out a suit before the hand begins. Who ever has the ace of the called suit becomes the partner and can play appropriately. However, when the called suit is lead both the picker and the partner must play the called suit. Because of this the picker can only call a non-trump suit they have in their hand.

A large glossary of terms accompanies the game. Terms like smear, leaster, schneider, burying the called suit/ace, etc. Yahoo games includes free online play for those interested in learning the game.