Double dick.

Just do shit to get back at them. It won't change anything but it will probably make you feel better. For instance, run around unplugging one random piece of hardware from every computer you see(mouse on one computer, keyboard on another, monitor on another, etc.) The IT guys will get so many calls from dumbasses who don't know how to use a computer and they will go nuts. I've also heard you can take a floppy disk apart and put gunpowder in it and put it back together and when you put it in the computer and it starts reading it will explode in the computer. Perhaps make a few of those and stick them in random shut down computers throughout the school so when the computers get turned on and start reading the floppies, they explode. Really, I'd just start doing stuff like that. Maybe not quite as entertaining as surfing the internet, but it could fill a bit of that void.

OH YES, WHY WHAT A PERFECTLY GREAT IDEA, LET'S BRING EXPLOSIVES TO SCHOOL AND PUT THEM INSIDE THE HARDWARE. NOBODY WILL EVER GUESS WHO IT WAS AND I CERTAINLY WON'T GET EXPELLED FOR TERRORISM.

I prefer magnets. They work better.