I'm from a latin american country and a game called casino is very popular (not to be confused with poker or actually casino games) It's a four player game with a partnership. Making it a 2v2. The first team to reach 21 points wins. The cards considered points are the aces scoring as 1 point. The 10 of diamonds and the 2 of spades both counting as 2 points respectively.
The dealer gives 13 cards to each player. This is where the games separates itself from spades or all fours. Instead of going by rounds and winning tricks or bidding how many points you'll get, the game is played by taking towards your team as many cards as possible. You do this by taking same numbered cards.
Example. The first player to play puts down a 4 (since it's advice to start playing low numbered cards) the next player decides, if possible, to take the 4 in the table with a 4 of his own. If he does he adds to the team card pool. If he wishes not to take the card or can't he has to drop another card. For example putting down a 3. Now the next player may choose to use a 7 he has in his hand and take both cards, (because 4+3=7) and so on and so forth.
Points start appearing when you add them to a certain card. For example if you know you have all four kings you can add an ace (which counts as a number 1) to a queen (making it 13 the numerical value of a king)
At the end of the round you count how many aces your team got or if you got the 10 of diamonds or the 2 of spades So that's the main difference with other trick and bid games. There are times where there are several cards in th table when the first 4 turns finish and players may choose to either take or add and combine cards.