The network space on my university campus was flat and unfirewalled - one big /16 on which every device had more or less unfettered access to every other device

The network space on my university campus was flat and unfirewalled - one big /16 on which every device had more or less unfettered access to every other device. Sometime in my senior year, I read that there was a PJL command that could set the ready message on networked HP printers. Naturally, I wrote a script that walked the entire /16 and would attempt to set the ready text to "Low Toner". My girlfriend convinced me not to run it, so I changed it to "Low Mayonnaise" and ran that instead. For the next few weeks, seeing "Low Mayonnaise" on printers was a pretty common sight. It disappeared on its own as printers were reset, or error conditions triggered, but it did feel pretty satisfying.