I recommend the Thursday Next series. It starts with The Eyre Affair by Jasper Fforde. It's about a woman who is a Special Operations agent in the literary department. It's a serious book, but it's funny.
Like, here is an exerpt from the third book (Pickwick is a pet dodo of Thursday):
"Sarcasm is better explained through humor," put in Gram, who had been watching my efforts with interest. "You know that Pickwick isn't too clever?"
Pickwick stirred in her sleep where she had fallen, resting on her head with her claws in the air.
"Yes, we know that," replied ibb and obb, who were nothing if not observant.
"Well, if I were to say that it is easier to get yeast to perform tricks than Pickwick, I'm using mild sarcasm to make a joke."
"Yeast?" queried ibb. "But yeast has no intelligence."
"Exactly," replied Gran. "So I am making a sarcastic observation that Pickwick has less brainpower than yeast. You try."
The Generic *they'll explain what those are in the book
* thought long and hard.
"So," said ibb slowly, "how about... Pickwick is so clever she sits on the TV and stares at the sofa?"
"It's a start," said Gran.
"And," added ibb, gaining confidence by the second, "if Pickwick went on Mastermind, she'd do best to choose 'dodo eggs' as her specialist subject."
obb was getting the hang of it, too. "If a thought crossed her mind, it would be the shortest journey on record."
"Pickwick has a brother at Oxford. In a jar."