I have written a tic tac toe game in Jack.
You can choose to be player X or player O.
It has 3 levels of play:
(1) easy - the computer plays randomly
(2) medium - the computer can only see 2 moves ahead, thus is beatable
(3) expert - the computer will never lose. If you play correctly, you will tie at best.
You can download the .vm code
here and run it in the VM Emulator and play around with it.
I am also happy to post the full Jack source, but I'm guessing since this is such a common project, maybe not. I will only do so if WBahn, the administrator, says it's ok.
Also, if anyone is struggling to make a tic tac toe game, I'm happy to answer any questions.
Here are some screenshots: