That's the game "Uno." The objective is to get rid of all of your cards (if you have one card, you say "Uno!" before someone else says "No Uno!" and you have to draw 2 cards, or whatever the house rules are. Putting cards down, you have to match the number (0-9) or the color (red, blue, yellow, and green). There are other cards, like "skip," "draw 2," and "reverse," which alter the course of the game. Wild cards are black, and change the color you put down, without having to use a colored numbered card to match. However, the deadliest card is the "Wild - Draw 4" card, which changes the color, and forces the next person to draw 4 cards. Basically, you can lose a friend with this card. ^_^
