One time someone figured out you could send an email to everyone in the university network with one command as everyone was in a Gmail group. That person started an email chain that lasted a few months.
When I got accepted to one university's CS program, they emailed congratulations to everyone who was accepted... on cc rather than bcc. I couldn't help but immediately take advantage of the situation, and the ensuing storm resulted in the admissions officer getting exceedingly angry and threatening revoking admission upon further misconduct. Fun times.