the sickest prank i ever pulled was me and my budies broke into the school late at night and flooded the basement where all the music stuff was kept. so all the tubas and drums and such ended up under water. they are still looking for who did it.
Well, I don't think this was my best prank--but it is the first thing that came to mind. Back in high school I went to a co-ed sleepover cross country camp. I don't remember what exactly the guys did, but they started the prank war! It was just small thinks like toilet papering our hall, or water balloon attacks. Then some girls and I had a brilliant plan. We snuck into their dorm in the middle of the night. We ripped open a bunch of tampons and dipped them in red Gatorade. We placed them all over the floor with a giant sigh saying "Is it in you?" (which was Gatorade's slogan at the time--dunno if it still is). The guys freaked out... haha it was a fun summer camp!