Something funny:
alias crontab='fuck you, <insert name of colleague here>'
Background:Everyone knows that in a [in]sane workplace, you ALWAYS have to lock your machine. So this particular new hire forgot to lock her machine and one of the seniors (senior prankster, I would say) jumped into her terminal and set a crontab to run EVERY MINUTE.
So she comes back (we pair program so they were actually pairing that day) and goes on with programming for a few seconds. Then she tells us to be quiet. We're all like "WTF?" She asks, "Do you hear some robotic voice saying something?"
At this point we're all trying to listen but to no avail. She thinks it's her machine (which was connected to a 27" monitor) and proceeds to max the volume. A few seconds later, the whole office hears a thundering robotic voice say "ASSHOLE".
Everyone laughs. From that point onwards, we all had shortcuts to lock our screens, and as an added "security" feature, we aliased our crontab to actually say "fuck you" to our senior prankster.