AIArena is a tournament where contestants write scripts for bots which battle each other in a virtual arena. I have written a dynamic web application which allows users to submit their own bots, written in a custom imperative scripting language dubbed BOTScript. The server will itself make the bots battle each other, ranking them on the website by how many wins each bot gets.
AIArena website: http://dank.business.com/bots/
If you have ideas, suggestions, feedback, criticism or whatever, drop me a line at firstname.lastname@example.org.