The "Sunday" computer virus, a member of the Jerusalem virus family discovered in 1989, contained a reference to the proverb. Infected files will contain the string "Today is Sunday! Why do you work so hard? All work and no play make you a dull boy! Come on! Let's go out and have some fun!" The virus's payload prints the proverb on the screen and then deletes all files running while the virus is a resident in the memory, as the original Jerusalem did every Friday the 13th.
