One of the many things we did was that we made a "spider web" in the courtyards with various strings (was actually really tiring running from one end to the other and got hectic when we ran into the strings that were in our way - also heard that a couple of teachers tripped over the thinner strings which made it a safety hazard); and also gladwrap (which was also used to wrap around the year 7's lockers so they couldn't get in haha) - this is the big supermarket deli styled glad wrap which someone took from work. The giant glad wrap roll was also used to wrap up the portable whiteboards, various trees and also buildings.
We also signed all our names with chalk onto a wall (was a big wall) and stuck for sale signs on teachers' cars (also had the school's number on them).
The school banned "sticky stuff" so we couldn't use make-up on poles/seats, honey/tomato sauce etc etc.