Cheer us all up - your favourite funny scene(s) in literature

Dorothy Sayers, Strong Poison - Miss Climpson's seances and her letters reporting back to Peter Wimsey. They have great funny patches, those books:

In a single moment of illumination, Miss Climpson saw her plan complete and perfect in every detail. It involved a course of deception from which her conscience shrank appalled, but it was certain. She wrestled with the demon. Even in a righteous cause, could anything so wicked be justified?
She breathed what she thought was a prayer for guidance, but the only answer was a small whisper in her ear, "Oh, jolly good work, Miss Climpson!" and the voice was the voice of Peter Wimsey.

Eleanor Oliphant getting her hollywood wax

Half Blood Prince- the muggle Prime Minister chapter.

Hard to pick favourite scenes from William, but here he is taking an intelligent interest in Shakespeare with a hapless substitute teacher

How could that other man Ham…”
“I said Bacon.”
“Well, it’s nearly the same,” said William. “Well, how could this man Bacon write them if Shakespeare wrote them?”
“Ah, but you see I don’t believe that Shakespeare did write them,” said Mr Welbecker mysteriously.
“Well, why’s he got his name printed on all the books then?” said William. “An’ if this other man Eggs…”
“I said Bacon,” snapped Mr Welbecker again. “I want first to tell you the story of the play of which you are all going to act a scene,” he said. “There was a man called Hamlet…”
“You just said he was called Bacon,” said William.
“I did not say he was called Bacon,” snapped Mr Welbecker.
“Yes, ‘scuse me, you did,” said William politely.
“Listen! This man was called Hamlet and his uncle had killed his father because he wanted to marry his mother.”
“What did he want to marry his mother for?” said William. “I’ve never heard of anyone wanting to marry their mother.”
“It was Hamlet’s mother he wanted to marry.”
“Oh, that man that you think wrote the play ...

(William the Pirate)

Can't think of one right now but just wanted to say excellent username.