This site, created by Nat Gertler, is a tic-tac-toe program written completely in HTML code. There's no Java and no CGI being used. Why did I do this? Simply because I could.
Please realize that you cannot win. The best you can do is tie.
This site is copyright 1996 Nat Gertler, all rights reserved. It is for sale! If your commercial site would be enhanced by this novelty item, please contact me via e-mail to firstname.lastname@example.org. I can create a version of this which is tough yet beatable, which might be better for keeping people on your site for a while.
If you find any bugs in it (if, for example, one position doesn't follow properly from the previous, or if you get a "File not found" error), please note the position before and after the problem, and e-mail them to me.