:time bomb: n. A subspecies of {logic bomb} that is triggered by
reaching some preset time, either once or periodically. There are
numerous legends about time bombs set up by programmers in their
employers' machines, to go off if the programmer is fired or laid
off and is not present to perform the appropriate suppressing
action periodically.
Interestingly, the only such incident for which we have been
pointed to documentary evidence took place in the Soviet Union in
1986! A disgruntled programmer at the Volga Automobile Plant
(where the Fiat clones called Ladas were manufactured) planted a
time bomb which, a week after he'd left on vacation, stopped the
entire main assembly line for a day. The case attracted lots of
attention in the Soviet Union because it was the first cracking
case to make it to court there. The perpetrator got 3 years in
jail.
-- The AI Hackers Dictionary