Gee - brings back a few memories

I wonder if we are doing the right thing by offering suggestions. Oh well:
Sneak into the girls toilets - put glad wrap over the toilet bowls under the seats and make sure all the lids are down - they probably won't notice as they sit down. But they soon will [}:)]
And another toilet one - plug up the water faucets really tightly - when someone uses them they will just turn the handle more and more until there is an explosion of water out of the tap.
Another really bad thing to do is shove toilet rolls down each of the bowls and push out of sight with the brush etc - may get a few overflows.
If you have any teachers that you really hate and they have a rather denigrating nickname - use roundup as suggested on lawn in a prominent location signwriting their name several days before.
We had a teacher with a mini - a few years before my muck up day about 20 yr 12's picked it up and placed it sideways in the driveway.