www.mikescher.com/www/statics/programs/TicTacToe_description.md

This is a really basic TicTacToe game. You can play against a friend or against a computer enemy.
The computer is intelligent enough to never loose, so all you can do is force a tie against him.

Because the sourcecode was that short it is directly included - perhaps someone is interested in the KI (MinMax algorithm)