Ultimate Tic Tac Toe is like normal Tic Tac Toe but on a larger scale and with an interesting twist. Whereas normal Tic Tac Toe will pretty much always result in a draw (for two reasonably good players), Ultimate Tic Tac Toe requires a lot more skill to master.
Ultimate Tic Tac Toe is 9 normal games of Tic Tac Toe played simultaneously. The board is made up of 9 tiles, each of which contains 9 squares. Your move will dictate where your opponent can play however. So if you play your piece in the top right square of a tile, then your opponent must play their next piece in the top right tile.
The first player get's to place their piece in any square on the board. After that you are are limited to the tile your opponent sends you to. There are two exceptions to this however.
If either of these occur then you get an open turn and may place your piece on any tile you like.
This is a great game to play: