In the end of middle school, the 9th graders:
1. Started a Food Fight
2. Put mysterious suitcases in front of classrooms
3. Ripped the fire detector out of the wall in a bathroom, setting off the alarm, and making us wait outside the school for the rest of the day while the fire department checked it out.
At the End of my 10th grade year, the seniors took apart a car, carried the parts inside, and rebuilt the car in the middle of the commons. It was funny as hell!

there was this bully at my school once and i tyed his t-shirt to the locker . and he couldnt get of =D ... he was picking on my mate when i was off ill.

Well where i live they went crazy.

1. tied there jackets around the handels of doors and lit the jackets on fire. NO one could get out for a while. Threw eggs at people. It was really funny but it was crap when you get hit with one which luckily I wasnt. And usually turned the fire alarms on non stop

i ripped off the keys of a keyboard and put space-key in the middle at computer lab. lol nobody wanted to use that keyboard anymore

ha

I remember back in my days at school people would mainly just throw eggs, and drive around shooting water pistols full of random substances.

One year though they took to picking people up driving them about 10 miles into the country side and leaving them there. Funny stuff.

I vaguely remember throwing water-baloons full of bleach at people in the 8th grade :v. But I have yet to have my year 12 prank.

last year some senior attempted a prank where he hacked into the schools computer system or something like that, and pretended to be the principal and he sent every teacher in the school a fake Email saying we were getting out at 10:00. Unfortunately he was found out because he said Ms in the signature instead of the full name. so he basically screwed up the signature

last year the yr 12's locked all their brothers and sistsers in lockers for an hour ....it hurt

At our school its a really loyal and funny tradition that the year 11's (as im from england we only have up to year 11's in senior schhol)
one of them or groups of them, a few days or weeks before the end of school for the year 11's, they would run out round the whole school shouting and rioting, and then, one of them will always set of the fire bell, which always makes the whole school go crazy etc, then they would start rioting again, my bro was one of them ;)
i actually find it funny as all the teachers take it so seriously for a bit of fun, even when they know that thats the tradititon of our school, and they know thats whats happening

Last year the seniors put baby oil in the hallways, was actually really stupid because one teacher fell and smacked her head on the ground and i was late getting to pretty much every class because half the hallways were closed because of the baby oil. The only other thing that seniors have tried while I've been in the high school is writing seniors on everyone's car. It makes me sad though because in years past they did stuff like putting porn in teachers VSR's without them knowing and they let out a bunch of mice into the school which are at least a little funny