The other thing we did was access network shares which you could see, but if you tried clicking them in explorer they'd say "access denied". The administrator apparently didn't lock things down very hard so a two-line .bat file:
We used to run executable versions of Quake and Tribes off the Administrative share. No need to install. Just run .exe and it threw you into the LAN game.
Our computers weren't that high spec but we did the same with scorched earth.
There was also evidence someone else found this before us because they had filled this one directory with viruses that had extremely obvious .jpg.exe extensions and basically various thirst trap stuff for creepy teachers filling the rest of the filename to click on it. I think I remember access to all of this was lost when this one kid was dumb enough to actually click something in there and he got blamed for it and expelled, which was pretty funny.
The other thing we did was access network shares which you could see, but if you tried clicking them in explorer they'd say "access denied". The administrator apparently didn't lock things down very hard so a two-line .bat file:
Would get us access to all sorts of crazy stuff.