Billy Tonkin's monster ate your friend's monster, and now it's time for payback. You're 5th graders, after all - it's your responsibility to make sure things are fair, and no 8th grade bully is going to scare you. All you have to do is gather up your friends, your monsters, and get across town to the Star Worlds Arcade where you know Billy will be, working on his Joust high score (which, to be fair, is impressive).
It's 1983, and this afternoon you ride - for justice.
(Monsters and Other Childish Things from Arc Dream Publishing uses the One Roll Engine also used in games like Godlike. I'll have dice and characters, and if we want we can make changes to the characters pretty easily. There will be 3 kids and 2 monsters, one having been, sadly, eaten.)