Holy Hand Grenade of Antioch

Full name: The Holy Hand Grenade of Antioch.

A reading from the Book of Armaments, Chapter 4, Verses 16 to 20:

Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."

^{From Monty Python and the Holy Grail, scene 21: The rabbit of Caerbannog}

The Holy Hand Grenade of Antioch was one of the sacred relics Brother Maynard of Camelot carried with him on the Quest for the Holy Grail. King Arthur used the Holy Hand Grenade to defeat the rabbit guarding the entrance to the Cave of Caerbannog so that the group could enter.

After a short reading from the Book of Armaments, as transcribed above, King Arthur took the Holy Hand Grenade, pulled the pin, and started counting. He almost ruined the plan when he miscounted: "One, two, FIVE!" Luckily he was quickly corrected. He threw the Holy Hand Grenade at his target, and blew the rabbit to tiny bits. The knights and Brother Maynard were thus able to enter the Cave of Caerbannog to continue their Quest.

Source: Monty Python's excellent movie Monty Python and the Holy Grail.

In the Fallout series of RPG computer games, there are many references to Monty Python. One of those is a special random encounter. You meet some men in power armor: they are knights, looking for the "Sacred holy hand grenade of Antioch". What most people don't know is that the weapon actually exists in the Fallout 2 game code. It's not available during the adventure, though: to get it you have to cheat, using the "Fallout 2 inventory editor" program.
It is thrown like a normal grenade, but deals an ungodly amount of damage (500, if memory serves me right), and will destroy most critters in one hit.

15/08/2005:
After a long time, I have reinstalled Fallout 2 and am in the process of replaying it. Since the last time I did so, the gamer community has managed to find the special random encounter in which you can get the grenade. It was meant to be available in the game, but in the end wasn't, although it isn't sure whether this happened because of a bug/glitch or on purpose. Anyway, a mod has been made to activate said special encounter. Look for it in Fallout sites.

The holy hand grenade is also featured in the game "Wizardry IV", although it is portrayed as the "holy hand grenade of Aunty Ock".