*** Version for iPad ***
"Tic-tac-toe, also called wick wack woe (in some Asian countries) and noughts and crosses (in the British Commonwealth countries) and Xs and Os in the Republic of Ireland, is a pencil-and-paper game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The X player usually goes first. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal row wins the game." Source: Wikipedia.
This game uses Game Center to post Leader Board.