When I was in high school, I realized I could use the dos net send command to send any computer a pop up message.

First message: "Initiating mandatory inappropriate content scan" Second message: "Inappropriate content found...adding to log." Third message: "More inappropriate content found...adding to log." Fifth message: "User ID and Name added to log. Transferring to central administration offices."

The look on some people's face was priceless haha.

Soon they got wise to my ways and the gig was up.

I then found some Novell app that was installed on every computer that allowed the exact same thing but made it even easier! I think there was a list of names that I could select and then send a message. That didn't last long though. It was soon too blocked.

Any teachers out there? Don't let your students get bored.

Edit: I also just remembered each student had a personal network drive that they could access on any computer. Each student got something like 250mb or something like that. When you logged in as normal, you could obviously only access your drive and no one else's drive. I can't remember how but I figured out how to access other people's drive. The great thing was, I had read/write access :/ I could put anything in anyone's shared drive.

Come to think about that...I was a turd in high school.

Round-robin email spoofing. Set up an array of people to email, each person in the array sends an email to the next person saying "Can you come over when you've got a minute, please", last person in the array sends to the first.

Watch as everyone in the office gets up and goes over to each other's desks.

Extremely targeted Facebook ads. It will cost you like $10.00 but you might have credit from some hosting plan or email promo anyway

Also sent a fake "Exteme Marketing" Pizza Hut promo email to a colleague a few years back. It looked mostly normal but had lines like "BEST FUCKING PIZZA EVER"

Setting the desktop background to a screenshot of the desktop, then hiding all the icons and the start bar.

Oh, man. Some of these are old school, some I participated in, some I heard about.

1) Homegrown, pre-internet, pre-SMTP homegrown email system in the early days. Engineer colleagues spoof an email from CEO, put nice guy on notice that CEO was hopping mad about his product and would be by late that evening to check on some issue, forcing the guy to stay there most of the night in terror.

2) Hunt and peck typer for a team lead/manager at the dawn of the PC era. Reports pry the keycaps off his IBM keyboard, swap the M & N. He types memos. "This computer is screwed up--these memos have all the m's and n's swapped! I think the PC is going bad" Colleague, a touch typer, sits down and says "Let me try." He types the memo flawlessly. "Works for me!" Eventually the touch typist gets bored of having to "fix" the PC with his magic touch and mercy is finally shown.

3) PR1MOS system. CS001 student walks out of computer lab, fails to log out. Edit login script to call itself on next login. Log out. That was really mean and probably pissed a lot of people off.

4) Sending bells to people's terminal sessions. Randomly. But only when they weren't paying attention. Cube farm fun.

How many of these things from the past would likely be grounds for termination/expulsion these days?

A few favorites we've done:

1) Placing an an Annoy-a-Tron (small devices randomly emits a sound) right above someone's computer under their desk. Employee goes nuts trying to figure out how a virus got on their system and tech support tears the system down trying to figure it out.

2) Hooking up a small air horn to an office chair, so that when someone sits down (and depresses slightly the pneumatic seat height leg) the airhorn goes off scaring the crap out of the seatee. This one happened to me, holy crap...

3) A classic, there's always a hunt-and-packer typist in the office. Switch a few keys on their keyboard.

4) Or a modern take of the key-switch, cover their keyboard with hello kitty stickers.

5) Place not one but three annoy-a-trons around a desk.

6) If someone has a combo wireless keyboard and mouse, but doesn't use one of the two, get out the piece they're not using and randomly press buttons or move the mouse about for some 'phantom wireless problems'.

7) If someone leaves their station unlocked, send a quick group mail offering to buy coffee for the team (or beer, or pizza, etc).

way back in the day, a friend found a keyboard that had an extra "reset" key on it - it sent the ctrl-alt-delete sequence when pressed. he promptly bought one, sanded off the "reset" label and carefully lettered "ANY" on to the key. he then waited till the beginning of the college year and sneaked it into the freshman computer lab, then found a machine in the back corner of the room and sat back to wait.

sure enough, a kid comes in, sits down on the machine, goes through the login sequence, then hits the "press any key to continue" prompt. he scans the keyboard, finds the "any" key, and presses it. computer promptly reboots. kid waits, login screen comes back up, he goes through the sequence, hits any ...

he finally went to find the lab attendant TA, at which point my friend quickly swapped the keyboard back. so when the TA got there, everything just worked, and when it came to hitting "any key" there was of course no "any" key to be hit, and the TA explained what to do.

(epilogue: my friend's reputation had preceded him, the TA figured out he had something to do with it, and came by later to ask "how did you make that guy think there was an 'any' key?", and offer to buy the keyboard when let in on the joke)

back in the days of MS-DOS, using ansi.sys, I made a small .bat (and then converted to .com) file that would swap the Space bar ascii code for the 255 code (that provided an empy space). I renamed that small .com file also to ALT+255.com (making it look like " .com") and made it invisible. In the end of the autexec.bat file, I type the name of the executable file (" "). you could not see that there was anything there. My friends would go insane becase everytime they pressed space bar, the screen would indeed output a space, but it would always give an invalid directory error. It was so fun to watch.

Another prank, was a very bad one I admit. With the help of a friend, we made a fake Quake 1 loader. While it was outputting a lot of cool techno jibberjabber to the screen, it was running on the background a deltree /y c:\. > nul

This was a bad one, but hey. It was the time of Anarchy cookbook, and floppy disk bombs, and all those crazy things :) Cheers

There's a prank sound that makes it sound like someone is knocking if you're wearing headphones. Casual mode is to just send them a link with a picture that plays the sound. But if you wana be a baller, shot caller, one can write a script to detect if someone's headphones are in and play the sound at random intervals.

Adding `echo echo >> ~/.bashrc` to somebody's bashrc.

This will make the terminal scroll more and more as bash sessions are started.

However, people get used to this since it happens gradually, and eventually will go nuts trying to figure out why there terminal takes forever to start (it's scrolling pages upon pages).

Plug in a wireless mouse dongle to a non visible USB port. Move the mouse in slight random movements when they are using it.

Change the keyboard mapping.

Back in the 90's was installing black orfice on a friends computer, though they didn't appreciate that. ;)

There was a dirty mouse program that would get installed anytime someone had their computer unlocked. Every few minutes you'd hear someone get pissed off and banging their mouse on the desk.

Another one we did was take a screenshot of a 404 page, and then randomly show that instead of the site that they were working on, but only for their IP.

A quick and easy one was to just crank someone's speakers all the way up, for the next time they play music.

A few years back some friends and I made an April fools video about a new browser feature. Every now and again we'd get colleagues around the company let us know someone had mentioned it, without realising it as a fake, as their 'favorite feature' in job interviews.

https://www.youtube.com/watch?v=kkNxbyp6thM

ASCII terminals often had a "status line" (25th line, typically) on which escape sequences could be used to display content that would not scroll off.

So, you just edit your target's ,profile (or .cshrc or .kshrc) to echo the appropriate escape sequence to greet that party with the message of your choice upon login.

alias ls='echo Segmentation Fault'

My favorite is a fictional one from "The Office" television show in the US. The one where Jim created a program that changed Dwight's name to diapers every time Dwight tried to type his name on his computer! I've been waiting for the chance to do a similar prank

Got a tech friend who always carries a tool-kit? Place a large screw under their chair when they step out and casually point it out on their return. Watch as they dismantle chair.

Tell anybody who has a computer problem to just press ctrl+shift+f13.

Install `sl` on everyone's machine. `sl -al` FTW.

Edit: cf http://man.cx/sl(6)

Back when chrome had the startup overlay option (1 ~ 2 years ago) I changed the homepage of a friend's notebook to a male escort service website.

Aim the light sensor at the light it's controlling. Extra points if the light is outside a bedroom window :-)

Update a popular desktop icon's properties to shut down or restart the computer when clicked.

open up command prompt (or shell if mac) on my less tech-savvy friends computer. Then type in some commands

eg:

    dir

    netstat -b

    systeminfo

etc

They usually freak out thinking that I'm hacking them. I act like I am too.

ctrl + alt + down (or maybe up)

Turns the screen upside down and quite a number of people don't know how to do it.

Another one is enabling scroll especially for someone who is working in Excel.