This might qualify!
LONDON: A 1,000-year-old double-meaning wry observation is what British academics consider to be their country's oldest joke.
They found it in the Codex Exoniensis, a 10th century book of Anglo-Saxon poetry held at Exeter Cathedral. It reads: "What hangs at a man's thigh and wants to poke the hole that it's often poked before?' Answer: A key."