Vault 69

Vault 69 was one of the Vaults created by Vault-Tec, and part of the Vault Experiment. Of the one thousand people who entered, there was only one man. Vault 68 was 69's counterpart, containing 999 men and only 1 woman.

Appearances
Vault 69 did not appear nor was mentioned in any of the Fallout games. It was mentioned in Chris Avellone's Fallout Bible, in a text which explained the Vault Experiment, therefore this Vault was either made up by Chris Avellone or came from the design document his text was based on. A concept art of Vault 69 was made by one of the Van Buren artists, which means that it was either to appear in the game, or the artist just did it for fun. It also appears in the official Fallout 3 One Man, and a Crate of Puppets by Penny Arcade.

Trivia

 * It could also be discussed about and/or speculated upon that the number of the vault is a reference to the sexual position of the same name, adding to the sexual nature of the vault's purpose.