Crazy Eights (a.k.a. UNO) is a popular card game played all over the world in different variations.
The object of the game is to get rid of the cards in your hand by playing them on the discard pile, where either the face or the suit of the card you play must match the face or the suit of the top-most card on the discard pile.
If you cannot play a legal card or if you do not want to play a card you must take a card from the stock pile.