Josh and Tony aren’t any great shakes on the basketball court—but with the fate of the planet on the line, they’re going to have to step up. A short story from Guys Other Worlds, edited by Jon Scieszka.
The Empire's invading forces are about to take over Earth, but they have 33,452 rules which must be followed before the invasion can begin. One of those rules states that warriors from earth must be given a chance to defeat warriors from the Empire. They choose a place which they believe is a training ground: a school's recess. This particular school's recess is playing basketball. When the "normal" kids fail, the invaders make sure that the braniacs are drafted. The brainiacs, named Josh and Tony, quickly realize that the invaders have a thing about rules. They defeat all the waves and send off the invaders. The Commander begins searching the rules for a way to retaliate against his mortal enemies.
Not my personal favorite of the short stories, but I could see others really enjoying this plot idea. Aliens from another plant have come to fight what they believe is a great army, but in reality are 6th graders having recess. After the more athletic kids are wiped out, Tony and Josh have to step up and get creative to save Earth.