A rule of table top gaming. If the DM/GM is being an Ass/dumbass/idiot and/or abusing rule 0, the players can choose to override him by leaving his game and starting their own.
An alternate version involves Smacking the DM over the head with the Dungeon Master's Guide.
DM: The ghoul rolled a 28 On his check to resist your Trip attempt.
Player: How the Hell does a ghoul get a 28?
Dm: With His +8 grapple modifier.
Player: But it is a Strength check, not a grapple!!
DM: I am the DM, Under Rule 0 I say He uses his Grapple Modifier.
This is where Rule 0.5 Is invoked
Every player at table: Smacks DM upside head with books and Leaves game.
by Eldrich Thurge January 30, 2009
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The phenomenon that denotes the homosexual rule. A rule that decides if you are either straight or gay-

1. If you define yourself as 100% straight = you are 100% gay.
2. If you got 0.5% gayness in you = you are 100% straight.
- "Hey bro, wanna touch my dick?"
- "Ew wtf, no dude" = 100% gay

- "Hey bro, wanna touch my schlong?"
- "Hell yeah bro, gimme that (no homo)" = 100% straight

0.5% rule
by Schlongdong123 September 4, 2020
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