In university, my uncle took engineering, and for a grad prank, since they're angineers, they figfured out how to hang a vokswagen beetle from the giant arc at the engineering part of the university of Calgary.
Another one they did was they had a rivalry with (i think) the geology departement, so one day they got ont he roof of the geology departments main buidling and took out all the students with a fire hose at about 6am before the early morning classes.
those are the only three i remember, theres more that he's done though. When im in grade 12 i plan to streak into the front doors of the school, unleash helium filled blow up naked dolls, and run out the back door into a car. Combo prank!