I just remembered a couple, not sure I submitted them already...
A friend who worked for a big drug company told me that there had been a young guy who had worked there for several years right out of college who got the chance for a promotion/department transfer. The new position required an FBI background check, so he filled out all of the paperwork, and included a misdemeanor drug arrest he got during college. However, HR noticed that the arrest was not on his original job application. When asked about it, he said that he was afraid he wouldn't be hired if the company knew. HR told him that it wouldn't have mattered back then, but by not listing it, he had submitted a false application, and not only would not be promoted/transferred, but also immediately fired!
Three weeks after I started with a telecom company (1996), another guy was hired for a different department. He started on Monday, filling out all the new employee paperwork, on Tuesday his Supervisor (who sat next to me) had him configure a couple of brand new database servers, on Wednesday morning, he got his company photo ID, on Wednesday afternoon, he got called into a Corporate Directors office and fired, when he came out, he was escorted off the premises! Supervisor wanted so bad to tell me why, but legally/ethically couldn't, so he let me guess. It wasn't that he failed the drug test, but something on his resume and/or job application didn't verify! Supervisor was ticked off, because he couldn't trust the work done on Tuesday, and he had to spend a day to reconfigure the servers, just in case!
This one is not a PD, but a year or so later, Supervisor (an ex-Marine sharpshooter) put a background program on a UNIX box in his cube that randomly made explosion sounds, from a pistol up to a field gun, at varying volumes. One day, when he was at another site, I was sitting at my desk, working on a preliminary design for a major project that I was in charge of, pencil in one hand, coffee cup in the other, when a very loud noise that sounded like every 16 inch gun on the USS New Jersey had just fired came from his cube! I managed to toss coffee all over that side of my desk, totally destroying the tablet I was writing on, plus a lot of naughty words came out of my mouth! I cleaned up, went to his cube and unplugged the speakers on the system, then copied my work to a new tablet! The next day, I told him what happened and gave him the coffee-scented tablet!
edited to correct a wrong word