If you take those caps and put a pin through the center of everyone and accordion them up the pin, then wrap them in scotch tape on all sides. Then take a regular matchbook match and stick the striker end into the middle of the accordion folds and light the other end of it on fire like a wick you have a Black Cat. You can also stand them on end so that the small end is on the ground and step on them and they will also go off that way all at once.

Now take a few of those into a six story staircase that just echoes any noise loud as hell, when the bell rings for class change run all the way to the top and put a few down and stomp on them just as the rest of the middle schoolers start pouring into the stairwell. I did not have a good summer break after that but for a few brief minutes my buddies and I couldn't stop laughing. This was also in the early 90's so school shootings weren't as prevalent then so I can't recommend doing that in todays environment.