Vault Boy's Big Book of Laughs for Kids
It was made by Vault-Tec, and is mentioned by Knock Knock, and the single known copy was found by Knock Knock inside the Little Lamplight caverns. Knock Knock says that the jokes are not very funny, and asks that the Lone Wanderer tell her some more. However, it is not seen ingame and is mentioned only by Knock Knock. It was probably distributed to all Vaults, although this copy suggests it may also have been sold in general, although it is also possible that it was from Vault 87.
Vault Boy's Big Book of Laughs for Kids is mentioned in Fallout 3.