Like Nicola, I enjoy slipping references into my stories. If people spot them, that really delights me. Currently, I'm writing a story set in Brighton in 1814. The Prince Regent holds an evening party at his Pavilion. In real life, if a possibility offered, he would entice a pretty young woman into a quiet room for a bit of dalliance. So in my story he plans to be alone with the heroine. To thwart him, Giles [the hero], places his friend, Ned, in the library. Only... Ned is a poet.
Behind him, he heard a footman yawn. A glance at one of the ornate clocks told him it was very late. There were only a few people left but Ned had still not appeared. Giles found him in the dimly lit library, deep in a book he had taken from the shelves.
'Nothing happened,' he assured Giles, when the latter had succeeded in rousing him from his story. 'Is it time to leave? Pity. This is a damned interesting tale.'
'So I see,' replied Giles caustically, 'Devil take it, Ned, there could have been an orgy in here and you would not have noticed.'
The 'interesting book' is a story by Jane Austen. The Prince Regent was a great fan and kept copies of her books in all his residences.