Tales of the wastes

 refers to an unmarked quest in Fallout 3.

Talk to Knock Knock in Little Lamplight. As she is the morale officer, ask her for a joke, then stay on her good side by laughing about her jokes and telling her they are funny. She then asks you for tales from the Wasteland and you can tell her you story.

This quest has basically 3 stages depending on your progress in the main story. At first you can tell her about your father and after The Waters of Life you can relay his sacrifice. Finally, your escape from the Enclave in The American Dream marks the end of your story as far as Knock Knock is concerned.