Well, my school has had some good ones over the years...
1. place A LOT of paper cups filled with water in front of all the doors so no one can get in without miving all of them
2. Park all the cars on the access road to get into school so no one could get in
3. Steal the maintenance golf carts and race them around not only the fields but also in the hallways
4. Push the principals car onto the patio
Other good pranks that were not planned but just stupid were:
1. Getting a car stuck in the baseball field after a winter rain and then having the field freeze up preventing them from getting it out... although a 12,000 pound winch attached to an International tow truck fixed that real quick! I have pics, but copyright issues prevent me from posting them- but HILARIOUS. ended up in a three-day suspension, though, so not funny for him. Actually, that would be a good prank- have everyone park their cars on the fields...
2. Another was riding a dirt bike down the bleachers in morning assembly- got halfway down and crashed, rider rolls down the bleachers and the bike went flying- BEST ASSEMBLY EVER! BTW- no injuries, amazingly.
OK, so long winded but just the start of the stupid stuff people have done, which could take days to type up. Most involve cars, water, or dirt. But I liked that cement girder plan A LOT- I might consider that one myself...
Ideas:
1. Disassemble a car and reassemble it inside a classroom or, even better, the roof.
2. Shut off the water main at the street or well and see how long it takes until they figure out how to fix it. !!!CAUTION- ThIS IS ILLEGAL IN MANY TOWNS!!!
3. Take over the PA system (if equipped) and blast music or inappropriate messages over it during class.