We haven't worked out all the details yet, but it will basically be who can make the tallest stack in a given amount of time (with tie-breakers being decided by fastest time back to the pad). We will publish the details after running a few tests and working out the kinks.
And in case everyone hasn't figured it out yet, the website is now live at
http://www.wpi.edu/News/Events/BattleCry/.