TicTacToe was always known to me as Noughts and Crosses but whatever you want to call it, it has to be one of the simplest games ever devised.
Which is why it's hard to justify why it needs a PC version (surely a simple pen and paper will do) but nevertheless, if you're a bit bored, Ultra TicTacToe will wile away a few minutes or hours. However, don't download it hoping to play against a friend - it's you versus the PC only.
Ultra TicTacToe features two difficulty levels - Easy and Hard and herein lies one of it's major faults. Easy level is ridiculously easy - you'd have to be pretty bad not to beat the PC at this level. However, Difficult level in Ultra TicTacToe is extremely difficult and no matter how many times you try, the PC always seems to have the upper hand or it ends in a tie. Since there aren't many variations possible in the game of TicTacToe, Ultra TicTacToe can inevitably become exceedingly boring but it's not designed to be played over a prolonged period of time to be fair.
If you love TicTacToe, have no one to play against and want to waste a few minutes, then Ultra TicTacToe is a good time filler - just don't try it on the hard level.