Fill a bunch of blow up sex dolls with helium and let them raise hell, only do so if your school has massive ceilings and cannot be taken down by the in-house lifts.
Kind of soft, but plant a fuck load of your state's flower on the football field. In most state's it is illegal to uproot the state flower. accomplish this by making a poster near said flowers warning the faculty of their potential crime.
Go on a spree in which a select group of people pull the fire alarm everyday for a week.
I almost managed this one, I had a class in the period prior to the when the school news team used one of the mac labs for the news. It so happened to be that i worked on the mac that the final cut of the news was uploaded to the previous Thursday. The newsteam teacher was notorius for being sloppy about editing, so one day I was going place a split second clip of porn between one of the pieces. this was almost accomplished except i wasnt able to manage to find a viable porn clip b/c of our school security. Shouldnt have been lazy and brought a flash drive for the job, it was an impulse idea on my part but could of had epic results.
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