Or...

So I've been thinking about what I saw re GameMaker in class (what it can do etc).

What if you were a bully behind a wall of snowballs. You have to hit the nerds running at the other end of the playground (but don't hit the girls!). If you hit the nerds twice, they go running off crying. If you don't, they start building a wall themselves to hide behind. Then they start building some smart contraption behind the wall that starts catapulting the snowballs back at you, knocking down your snowball supplies until they've hit you enough times that you go home crying. You would have to take time to build snowballs while hiding behind your wall sections (which also act as supplies). As you build snowballs, you would then drop them into bare sections of your wall and when you want to fire them at the nerds, you just click on the wall section. That could be interesting...