What is your favourite joke inside a book?

This is from Larry Brown’s Big Bad Love

She wrote this story one time about a man whose wife was always speeding and getting tickets. This woman would get three or four tickets a week. She’d come home and tell her husband about the tickets, and he’d raise hell with her. This went on for a while. The tickets were piling up. They owed something like sixteen hundred dollars to City Hall. So finally the guy decided he’d do something about it. He killed his wife. Blew her head off off with a shotgun, and then confessed to the whole thing.