Play Connect 4 - over the internet - in 3D. In this classic game, players take turn dropping chips onto a vertical board. The first one two connect four in a row wins.
Click on the row you want to drop your chip into, and just align 4 (either vertically, horizontally, or diagonally) to win.
If you're a Connect 4 pro, you'll manipulate your opponent into playing into your hands by dropping their chips right where you want them.