Asklemmy

I had GLTron and Pocket Tanks installed on a flash drive, so my friends and I would just play games whenever we had free time.
I also found a couple fun network based utilities in Windows, and all the computers in the district were on the same network. I was messing with NetSpend one day and managed to accidentally send a message to every computer in the school, which then all promptly crashed for some reason.
I also had fun messing with the netchat application. My mom worked at another school in the district, and one time I arranged for her to open netchat at a specific time while I was in computer lab, so I could connect to her computer from a lab computer and we could chat back and forth.

We could unscrew the chassis of the computer and take whatever hardware we wanted to lol. We never actually got anything but we'd remove the RAM or unplug a hard drive and put it back.

We also found games hidden in certain directories. I even saw someone playing Undertale.

I also found a torrent client running on start up on one of the desktops seeding some movies.

If it counts, we used a program to throttle other devices' WiFi speeds. I forgot what it was called.

installing linux as dual boot, well it fixed the windows 7 that couldn't update lol

I used to goto cartoon websites and play unallowed computer games, nothing inappropriate, just spongbob stuff, which got me permanently banned from watching spongbob at home.

The school would keep using Internet Explore 6, I'd update it to iE 8. They didn't like that.

I'd also would install some toolbars, there was this one yahoo one, that added tabbed browsing to iE6. :)

Updating to iE8 on only one older computer caused problems, but the newer machines worked fine with iE8. ;)

I would install Firefox, Opera, Google Chrome and Apple's Safari for Windows web browsers. I enjoyed testing and find the best browsers back then.... Staff weren't to happy though.

I'd change desktop wallpaper to windows XP's Bliss, instead of the schools preset solid colour background.

As i got older, I learned how to write batch and vbs scripts to automate different things, so i wrote a tool to automatically login to some of my required school accounts, without me needing to manually type in my login credentials each time. Staff either didn't know or didn't mind this.

We installed Doom (1 or 2, I don’t remember) in an invisible folder and played via the 10Base-2 network. Those were the 90ies…

We never had school computers :(

We installed Doom on a couple computers, this was in '97. Our computer teacher had absolutely no idea how we did it. Private schools were fun for running circles around the teachers.

I used them as a sort of thin client into a system that I had root on, so I could do whatever Science demanded of me without asking for access. Permitted, but certainly unexpected!

I would carry a USB stick that just had a VNC client on it. My home server was built from high-end scrap, and was leagues faster than anything the department had at the time, at least for student use.

I also had a Sharp Zaurus I had jury-rigged WiFi into, so I could run data analysis whenever I thought of something. It ran VNC or SSH. This was in the early days before it was called "machine learning" or even "big data". So we take this sort of thing for granted now (hello Google Cloud), but at the time it was magic superpowers to have immediate access to a machine with 4 physical CPUs from a handheld device.

Background on a lab to a high resolution naked mole rat picture zoomed in so it kinda looked like a scrotum maybe, but it wasn't: It was just a naked mole rat.

While not technically a school computer. In college we all had to install a WiFi client to access the school's WiFi. It was shit so I started digging around and found the localization files in plain txt. I then, when I had the opportunity to, booted into a friend's computer with Linux and changed the confirm button to say "I'm a bitch". They never asked me to change it, which I would've, so it just stayed like that all year.

In graphic arts I would hit the PrtScan of the desktop screen and put it into PowerPoint. Then you just use the marker/highlight option and draw phallic.. things.

Our teacher thought someone used permanent marker and would leave the room to cool off while we just stopped the power point presentation and goofed off.

Netbus 1.70 baby

Set up fork bombs to trigger at random intervals.