Using the standard deck of cards, each player tries to have the fewest number of cards at the end of the game. All cards are spread out face-down in the middle of the game like the shape of "pig tail". Everyone starts with no cards in his/her hand. In your turn, you either flip a card or play a card from your hand. If it is different color and different number form the previous one, then it stays there. Otherwise you take all the face-up cards to your hand. The game is over when there is no face-down card in the middle of the table.
There are a lot of games with similar rules. This one is particularly strategic. As there are only 2 colors (black and red), you really want to time when you start decreasing the hand size. It is all about timing.
The game is strongly recommended for even number of players like 4 or 6. The game is nearly as good with 3 or 5.