Coil is a 2-player connection game on a hexhex7 (or larger) board, where one player is trying to form a loop of stones in his color, while the other is trying to prevent the loop's formation. There's a "chicken ballot" at the beginning of the game to ensure that the two sides are balanced. Because loops come in a wide range of sizes and shapes, and have many degrees of freedom, the game has rich tactics and strategy. Small loops threats force players to focus on local battles while large loop threats force them to think globally, and to consider how the local battles fit into the global war.
Complete rules, along with printable play meterials can be found here:
http://nickbentley.posterous.com/new-game-coil