From the website:
Be the first to play all of the cards in your hand. It's that simple. or is it? When it's your turn, lay down cards in your hand that make sets (3 or more of the same value) or runs (3 in a row of the same color) or play cards on another player's piles to get rid of your cards faster. For those who really like to explore all their possibilities, transport cards from other piles to combine with new cards, and make new piles. Just remember, each pile must always have at least three cards. The possibilities are out of this world!
The Action Cards make INFINITY even more fun. Give every one of your opponents three extra cards when you play the Re-Fuel card. Get new cards to replace the ones in your hand with the Re-Entry Card. Or play the Countdown Card to force someone to make a play and gain control of the board. Don't wait for your turn, either, play any of these any time you want!