The Legend of Zelda: The Four Swords

What makes Four Swords so fun is the communication and cooperation it requires between the players. As few as two players can work their way through the game together, but it's infinitely more fun with a full roster. The dungeon puzzles have been designed to demand that multiple heroes solve problems and slash foes together, but even as you cooperate, you compete against your friends to see who can collect the most Rupees. The ensuing action is pure multiplayer bliss.

The more you play Four Swords, the more of Four Swords there is. Every time you play, the dungeons are different than the last time you plundered them. Four Swords creates a dungeon level by randomly selecting a dungeon setting -- a vast area with many set challenges -- then dropping a randomly selected new dungeon part into it. As you gain more keys and experience, obstacles become more challenging and levels become more difficult. There are dozens of settings and parts available for each separate area, so you'll always be challenged with new dungeon levels!