Congratulations! Mine was intentional, back in college, where all PCs had open telnet in order to facilitate cooperation. We discovered it was easy to seize someone's computer for a while, and then watch them look around for the culprit, which we thought was hilarious. Boy were we annoying.

My first was in college on the lab computers, I was like "can I create a pthreads bomb instead to circumvent the fork bomb protections?"

Luckily the head sysadmin knew me and was in the room at the time, and I sheepishly explained by the time I realized it worked it was too late for me to stop it, he seemed understanding, understood it wasn't malicious, and luckily got that what else is a CS department for than for students to learn about this stuff?

How did you not get caught??!?