This year they've added a level-generation aspect to the competition.
The level generation track of the competition is about creating procedural level generators for Infinite Mario Bros. Competitors will submit Java code that takes as input desired level characteristics, and output a fun level implementing these particular characteristics. The winner will be decided through live play tests.For more information, visit the 2010 Mario AI Championship page.
They also have competitions based on Ms. PacMan, StarCraft, and others.