1. Harry Potter and JK Rowling (the author) share the same birthday of July 31st.
2. Fred and George Weasley were born on April Fools Day
3. In one of the first drafts Ron Weasley swore like a sailor, but JK Rowling’s publisher made her cut the cussing out.
4. Alan Rickman, the actor who plays Professor Snape, was told by JK Rowling that she was going to kill off his character before the release of Deathly Hallows.
5. Dementors were inspired by Rowling’s personal experiences with depression.
6. Dumbledore was reluctant to kill dark wizard Gellert Grindelwald because he had fallen in love with him.
7. There are 700 different types of fouls in Quidditch.
8. Speaking of Quidditch, Professor McGonagall was once a widely respected player.
9. Slytherin House has slowly become more moderate since the conclusion of the series. It now containers some non-pure bloods.
10. Arthur Weasley eventually fixed Sirius Black’s motorcycle and gifted it to Harry.
11. Harry himself, worked as an Auror, as did Neville Longbottom before becoming the Herbology Professor at Hogwarts.
12. The scene in the Goblet of Fire where Hermione teaches Viktor Krum to pronounce her name was written because so many readers struggled with it.
13. Speaking of Krum, he eventually got over his love for Hermione and married a Bulgarian woman.
14. An anagram of “Remus Lupin” is “primus lune” which is Latin for “first moon.”
15. Lavender Brown is an anagram for “brand new lover.” JK Rowling really really liked wordplay.
16. There about 3,000 wizards in Britain.
17. Very little is known about the magical community in the United States.
18. JK Rowling did mention that Voldemort’s rise had an effect in America, suggesting that he may have had plans to invade there.
19. The American wizard governing body is the “Magical Congress of the United States of America,” and the current President is Samuel G. Quahog.
20. Kings Cross Station has multiple “fractional” stations for wizard use. 9 3/4 is, of course, the Hogwarts Express, but for example, platform 7 1/2 is the Orient Express.
21. Aunt Marge was in love with one of her neighbors on the street, and this unrequited attraction contributes to her bitterness.
22. Before getting moved to Defense Against the Dark Arts, Professor Quirrell taught Muggle Studies.
23. Harry Potter in adulthood is known to return to Hogwarts occasionally to give lectures about Defense Against the Dark Arts.
24. Dolores Umbridge ends up in prison in the future, which I think we all really wanted to see on screen.