Mariáš (the final sound is pronounced as "sh") is the most popular card game in the Czech Republic and Slovakia, often seen being played in pubs. This trick-taking game is the basis for Ulti, the national card game of Hungary.
It is played with a 32-card deck, similar to the William Tell deck but with specific Bohemian art. There are four suits: hearts, bells, acorns, and leaves, each with eight cards: ace, king, over-knave, under-knave, 10, 9, 8, and 7.
The most common setup is with three players, with one player playing alone against a partnership of the other two for each hand. The lone player seeks to win more card points than the other two players together. Points are received for winning aces and tens in tricks, winning the last trick, and for the combination of king and over-knave of a suit. There are also several bonuses and penalties that affect the final score.
(Description borrowed from Mariáš page on pagat.com)