Interesting things
Here are some interesting things I've read or noticed about the series. This is also where I'll post things that don't really fit anywhere else.

The Mirror of Erised: Backwards, erised is desire
When looking at objects in the mirror you see them backwards, "Erised stra ehru oyt ube cafru oyt on wohsi" spelt backwards is "I show not your face but your hearts desire"

The four mascots (I can't think of the word I'm going for) are: Gryffindor: Lion, Ravenclaw: Eagle, Slytherin: Snake, and Hufflepuff: Badger

Hogwarts Motto: "Draco dormiens nunquam titillandus" is in Latin and means "Never tickle a sleeping dragon."

On the entrance to Gringotts Bank it reads:
Enter, stranger, but take heed
Of what awaits the sin of greed,
For those who take, but do not earn,
Must pay most dearly in thier turn.
So if you seek benaeth our floors
A treasure that was never yours,
Thief, you have been warned, beware
Of finding more than treasure there.

Hogwarts School Song:
Hogwarts, Hogwarts, Hoggy Warty Hogwarts,
Teach us something please,
Whether we be old and bald
Or young with scabby knees,
Our heads could do with filling
With some interesting stuff,
For now they're bare and full of air,
Dead flies and bits of fluff,
So teach us something worth knowing,
Bring back what we forgot,
Just do your best, we'll do the rest,
And learn until our brains all rot.

My favorite quote:
"He therefore had to endure over an hour of Professor Trelawney, who spent half the lesson telling everyone the position of Mars with relation to Saturn at that moment meant that people born in July were in danger of sudden, violent deaths.
'Well that's good .... just as long as it's not drawn out. I don't want to suffer.' "

The following items are things I picked up in Goblet of Fire that I want to share. If you haven't read it yet, go back now.

The riddle of the Sphinx:

First think of the person who lives in disguise
Who deals in secrets an tells naught but lies.
Next, tell me what's always the last thing to mend,
The middle of middle and the end of end?
And finally give me the sound often heard
During the search for a hard-to-find word.
Now string them together and answer me this
Which creature would you be unwilling to kiss?

At the end of the book, Dumbledore tells Sirius to round up the old crew. One of the names he mentions is Arabella Figg. Remember that Harry's old baby-sitter is named MRS. FIGG? Voldemort tells Harry that Dumbledore set up his future for him, making sure he would always be protected while in his relation's care. And when not in their care, he still would be safe while in the care of Mrs. Figg - A WITCH!!

When talking with his Death Eaters, Voldemort comments on the ones missing. One of these missing Death Eaters he says he fears "has left him forever. He will be killed, of course." This Death Eater he was referring to is Snape. That's why Snape is a teacher at Hogwarts - if Voldemort is afraid of Dumbledore and wouldn't attack Hogwarts, Snape will also be safe under his eye.
The Location of Hogwarts!!!
I have recently stumbled across this… it happened when I was looking through Fantastic Beasts & Where To Find Them. I was reading the first beast “Acromantula”, as we all know is Rons biggest fear, being the biggest spider in the wizarding world. It mentions at the end of the caption “Rumours that a colony of Acromantula has been established in Scotland are unconfirmed”. In scribble form it has the unconfirmed crossed out and replaced with “Confirmed by Harry Potter and Ron Weasley”. The readers of the Chambers of Secrets know that Harry and Ron have a run in with a colony of Acromantula in the Forbidden Forest. So if Hogwarts is outside the Forbidden Forest that must mean that Hogwarts is in Scotland to!!!