Gomoku is an extended version of Tic-Tac-Toe, played on an infinite board (approximated by a 21 by 21 board in this version) where the winner is the first player to get 5 in a row, orthogonally or diagonally. You get to go first, and an X marks your squares. The computer plays the O's, and is remorseless and unrelenting. Since this is a Java applet, you need a Java-enabled browser to make this work. Good luck!