We filled our P.E teachers offices with balloons, bout 1200 in total. But as Mack said be careful, we only did it cause we were all on teams of sorts and knew the coaches well. It would suck to have anything happen that might put your chances of leaving high school in your final year in the hands of an administrator.
If you want something fairly innocent just have a BB-Q in the staff parking lot... Just get all the students in the parking lot before school and block off all the entrances with cars... and get people with trucks to bring BB-Q's... Bring ping-pong tables and kiddie pools water guns... footballs... soccerballs... beachballs.... just pretend its a beach party or something. O ya and get someone with a crazy stereo system in their car to pump tunes... just make sure you know how to jump start a car when the battery runs out
some seniors drained our pool, and managed over a weekend to fill the whole thing with sand.....im not sure if they bought it and had a company do it or if they just brought a bunch of trucks back and forth from the ocean, but you should of seen the look on the staff's face priceless....also it took the school and a company to remove all the sand about 3 weeks the kids did it Friday night threw Sunday like 2am supposedly has to be the best.
my sister called from a school phone order out form like 10 food chains from each like $200+ worth of food to be delivered to the principal, week later she called for a crew of like 10 strippers to come to the principals home at like 1am and she slept over a friend that lives across the street from him and got it all on film LOL
My rival high school has a fence around it and is near a canyon. So the seniors thought it would be funny to throw about a dozen chickens over the fence so they would be running around when the admin got there. Well, the idiots forgot the chickens can fly, so SPLAT! The chickens landed, died right near the fence and when the admin showed up... The chickens hadnt gone anywhere, but now there were a dozen chickens lining the inside of the fence, and about a dozen coyotes on the outside trying to get the chickens