I guess I'll contribute my best prank.

In the late '00s I was working at a small ed tech company that had recently moved into a nice new HQ with a large kitchen. They got this pretty fancy popcorn maker and the IT team put it together (I was a dev, so I was not on this team). People kept burning the popcorn, so it became the office/facilities manager, Tim's duty to make the popcorn (which he was not exactly happy about).

I was in the IT closet looking for some cables and noticed a bunch of spare networking equipment laying around. So I grabbed an old four-port switch, an external wifi antenna, and some cables, then I stayed late one night and "installed" them on the popcorn machine in a manner that was surprisingly convincing. IoT Popcorn machine before IoT was a thing.

I also wrote up a script that would connect to our Outlook server, and send an email to Tim, "FROM: TECH-POP <techpop-machine@companyname>" with "SUBJECT: TECH-POP IS READY TO BE REFILLED" and some techy-sounding status updates in the body of the email. I even kept track of the number of popcorn bags remaining in the cabinet.

Once every few hours, I'd run the script, and Tim would dutifully get up and make some popcorn. After about a day, I ran the script and heard loud, "GOD FUCKING DAMNIT", and the slamming of a chair. Tim went over and ripped all of the networking stuff off of the popcorn machine and threw it in the trash. He then paid a visit to the IT manager to clarify who it was that thought it was his job to "refill the fucking popcorn". The IT manager, with a completely straight face, gets up and I see them walking my direction.

They get to my desk, and the guy is coming down from being piss-pissed. His face is all red and eyes are watering. The IT manager tells him, "it was this fool's idea." They laugh and say it was a funny prank and Tim playfully grabs my collar and shakes me a little.

After that, I get a message from the IT manager to avoid pranking Tim in the future.