Paul Reinheimer has posted about a contest in the making - a turn-based robot battle sort of game where PHP scripts compete against each other.
Just a quick announcement, in an effort to come up with a self scoring contest, I came up with the ridiculously simple concept of robots firing lasers at each other in a fictional arena. Each robot controlled by a different PHP script, and a central arena managing it all. It's basically a turn based game where your robots take turns for you.
You can check out more about the game and its rules over on the Web Bot Battle site. It defines how your bots should act and even has some examples for you to work from.