School Prank ideas?!?

I need some good school pranks to play, i go to a really strict school and everything is so boring and i dont want to remeber school being strict and dull etc, so ive decided its up to me to start pranking and making history! i have some basic pranks like vaseline/honey on doorknobs, clingfilm on toilet seats, and dead fish behing the radiator, but i need something original and new, so if you have any ideas please help me :)