Mus is a very popular card game in Spain, where until the arrive of the Texas Hold'em variety of poker, it was the most played game.

The mechanic is so similar to poker, but you have to play by couples, two vs two. There are four plays: "grande" (big), "chica" (small), "pares" (pairs) and "juego" (game), and you have to obtain at least 30 points to win a "vaca". When you win two "vacas", you win the game.

It's difficult to explain here, but if you know some spanish and you want to try, search in internet and probably you'll find lots of information.