Hi I just bought my Arduino yesterday and it is real fun using it. I set up TicTacToe with 9 LEDs on a breadboard. Here is the video of it in operation:
A flashing light means a free space, switched on means player one and switched of player two. Input is done by serial console.
If there is interest in further information, I will provide. Disclaimer: If this game was already implemented, i didn't find it.