Euchre is a trick taking card game played with a partial deck. All cards lower than 9s are removed. Four players play against each other in two teams, and each player is dealt 5 cards. After the players are dealt their cards, a card is dealt face up. Each player has a chance to decide if they would like this card's suit to be the trump suit by ordering the dealer to pick it up and discard a different card. The team that decides trump must win 3 trick to get a point. If the opposing team wins 3 tricks they get 2 points. More instructions here.
How to play Euchre