Schwimmen or Thirtyone is a popular card game from Germany/Austria that is also gaining ground in the US. It is a commerce-type game where you exchange cards with open cards on the table to increase the value of your hand.
The object of the game is to get as close to 31 points as possible with 3 cards of the same suit. The ace is worth 11 points, the king, queen, jack and ten are worth 10.
The other cards (9, 8, 7) are worth their face value.
At the start of the game each player is dealt 3 cards and 3 cards are also placed face down on the table. The first player can accept their hand or exchange their hand with the cards on the table.
After this the cards on the table are turned face up and the next player (clockwise) plays first. At your turn you may exchange one card from your hand with one of the cards on the table.
In the first and last round, if you do not want to exchange a card you may pass instead. You are always allowed to pass after your turn.
Instead of exchanging one card you can elect to exchange all your cards with the cards on the table. In this case you pass automatically.
When all players except one have passed, that one player gets one more turn before play ends.
When a player has 31 points his/her cards are turned face up and all players get one more turn before play ends.