In the early 80's, there was a girl working in the geology department at the gold mine i was at.
She was a fair B... Well, not a nice person.
When she was away from her comp, one of the mining engineers changed her dos prompt from C:\> to C:\Now formatting harddrive> (i think that how it looked using "new prompt" command).
She came back in a hurry to print of a doc for her boss, seen the change, tried to print, but would not work.
Turned out it had a loose connection to the printer at the same time. All hell broke loose, but all those in the know, couldn't speak. They were all doubled over laughing.
After that joke, she became an even BIGGER B... You know, NOT nice person, lol.