Only time I got yelled at was when the teacher saw the SSH window open and yelled at me for being in the command line. So I changed the colors to black text on a white background and they never said anything again.
Once I burned a bunch of Linux boot cds with unreal tournament on them and took over a computer lab to have a lan party. That was fun until the lab monitor got spooked that his monitoring system showed all the computers as turned off when clearly the lab was full…
The most notable is probably cracking the admin password because I wanted to change the volume or something. (Seemed perfectly reasonable to me at the time!)
The computers had all kinds of weird restrictions, including the panning being forcibly set way to the left to compensate for the school's crappy headphones -- a crime against humanity, you would surely agree, if you experienced it.
It took 30 seconds to crack, it was a short dictionary word and I remember being very disappointed with the sysadmin. But obviously I couldn't tell anyone about it...
Let me see what else... our school accounts had 200MB network storage, but this was too small for all the Portable Apps[0] I wanted to use. So I created some kind of "startup program" that downloaded and extracted them from my web server. I think it also changed the background and the Windows Theme...
https://portableapps.com/apps - still online, I see!
I think these days kids just have their own laptops though. That's no fun at all :)
That reminds me of how in zoos they put the food inside hard to open boxes so the animals don't go insane from boredom.