When I was in grade 10, the grade 12 graduating class pulled a prank using bouncy balls like this that will go down as probably the best prank ever at my high school.
We had a large gathering area that could seat about 400-500 students that was situated directly below a walkway/balcony on the second floor of the school. During the last week of classes, a couple of grade 12 kids dropped a bag of about 500 bouncy balls down into this open area (a drop of about 15 meters), and madness ensued for about 10 full minutes.
I'm talking insane and utter chaos. Students flipping over tables for shelter, balls whizzing in every direction, people getting pelted with projectile rubber balls, girls screaming and crying, teachers yelling and grabbing students who threw balls at each other. It was awesome.
And it was only about 500 of those things. The magnitude of what they did for this ad is not lost on me, that's for sure. Way cool.