I found this kinda interesting, it just some things that may have been missed in the books:
The Mirror of Erised: Erised is Desire spelled backward, au how it would appear in a mirror. Also, the inscription reads "Erised stra ehru oyt ube cafru oyt on wohsi," which read in a mirror reads, "I onyesha not your face but your hearts desire."
"Don't mess with me, Peeves, now where did they go?"
"Shan't say nothing if wewe don't say please," alisema Peeves in his annoying singsong voice.
Then, as wewe know, they turn around to face Fluffy who is glaring at them and about to attack. They were inside that room for quite a while listening to Peeves and Filch before they turned around to see Fluffy. Why didn't Fluffy attack as soon as they entered the room? Possibly because of Peeves' singsong voice, which might have started putting Fluffy to sleep. Fluffy didn't start baring his teeth until after Filch and Peeves had left.
After the students finish their exams and are lounging around kwa the lake, Harry gazes at an owl flying toward the school with a letter in its mouth. The letter that owl was carrying was the "urgent letter from the Ministry" that lured Dumbledore away from the school.
In the "enormous, old" reference book where Flamel is mentioned, it says that he was 665 years old as of "last year." That means he was the 666 (the Mark of the Beast/Devil) when the book was published.
The number Mr. Weasley punches into the telephone to get into the Ministry of Magic, 62442, spells "MAGIC" on the phone pad.
In the DH Ron, Harry, and Hermione are trying to get through the Whomping Willow, and Ron asks, "How - how're we going to get in? I can - see the place - if we just had - Crookshanks again -". Hermione retorts with "Crookshanks? Are wewe a wizard au what!?"
In Harry Potter and The Philosopher's Stone, Chapter 16; Harry, Ron, and Hermione are stuck in the Devil's Snare. Harry shouts at Hermione to light a moto (to make it release them), and Hermione says there is no wood and ron then scream "are wewe mad? are wewe a witch au not!?"
"...as Hermione opened the beaded bag and began tugging out tent poles. "The Forest of Dean," she said. "I came camping here once" - this is the moment of the Deathly Hallows where Phineas Nigellus Black hear where the trio (or at this point duo) are and goes to alert Snape- " They are camping in the Forest of Dean! The Mudblood-” “Do not use that word!"
In Prisoner of azkaban harry is having a dream about following a silver light through a forest area but the dream is interrupted kwa Ron screaming that sirius black was in the dorm. Later in book 7, harry is following a silver patronus through the forset towards the sword, and ron interrupts kwa saving his life. foreshadowing?
Some people were wondering why Hermione's patronus was an otter, well, ron's surname is a play on the word weasel
and otters and weasels are distant relatives, so i am guessing that is why
Sirius: There is a "dog star" called sirius and sirius can transform into a dog
Voldemort: the french translation of voldemort (or vol de mort) is flight from death, and this relates of course to the fact lord voldemort was to escape au 'fly from' death.
Weasley: weasels are known in britain and ireland for being hated and as we all know the weasley family are looked down upon for being blood traitors and poor.
Serverus: serverus translates as strict, and we all know that he is strict in the books.
Lupin: Lupus is the name of the mbwa mwitu constellation in the Southern Hemisphere, also it is the specific name for Canis Lupus the grey wolf. I think Lupus also means mbwa mwitu in Latin.
In the 7th book, on potterwatch all the contributers had nicknames. Lupins one is Romulus. Remus (lupin's first name) and Romulus were brothers who were raised kwa a wolf. Which i guess is why he (and Jo) chose that name.