Get a bunch of palm sized rocks and note cards put the rocks around your school where people can find them on the note cards wright random stuff on them and make people think the rocks are talking to them like how did i get here i just woke up or im a bit late but i cant move can you pick me up and take me with you where ever you go. stufff like that ish i cant think of anything good right now i just took the E.O.C Test ....DO THIS IT WILL BE GREAT! oh! and put the notes under the rocks but make the notes visible
Here are a few that we've done at my school: Tape a paper with the word "Dumble" on all the doors. Duct tape a teacher to a rolling chair and race her down the hall. Get a ton of balloons and blow them up, then put them in a classroom.
set off the fire alarms or flood the school or lock the principal in a closet or steal the flag and put it up in front of your house or rip out every single grass around your school or you can sit and stare at the wall the whole time with a group of friends and see what people do
Stand outside looking up at the sky and ask a fellow prankster "when are they suppose to fly over?" They answer, "they should be here by now, lets go call and find out if they are having trouble or are just late." See how many stand there looking after you leave. We did that and all kinds of people just stood there. Some others came up and some of the gazers told them the Blue Angels were about to fly over. LOL!! What fun that was!! Create your own non dangerous prank. Rave on!!!