Pottermore

[Marry The Night]

"Pottermore is an exciting new experience from J.K. Rowling based around the Harry Potter books. It is FREE to join and use, and is designed to be safe for people of all ages." Users will be sorted into Houses, receive wands, and can unlock certain bits of information.

For the next seven days, from July 31st to August 6th (day 1 of registration is now closed), a clue will be posted on the Pottermore front page -- answer correctly (and quickly), and you'll gain early access to Pottermore. Each clue will relate to a different book in the HP series (for example, the clue for day 1 [today] was related to Harry Potter and the Philosopher's Stone - the first book). Pottermore will open to the public in October. More information on early access and clues can be found on the Pottermore Insider blog.

EDIT: The beta is now over, and Pottermore is now open to the public. Students can currently explore Book 1 and four chapters of Book 2.

Spoiler for Potion Ingredients and Locations:

NOTE: If you're an avid potion brewer, finding these potion ingredients within the chapters is a great way to save a few Galleons.

The Philosopher's Stone Potion Ingredients:
Dried Billywig Stings - Chapter 8, Hagrid's House, Layer 1
Dried Nettles - Chapter 8, Hagrid's House, Layer 1
Wolfsbane - Chapter 8, Hagrid's House, Layer 1
Eels Eyes - Chapter 9, The Trophy Room, Layer 3
Bat Spleens - Chapter 10, The Mountain Troll, Layer 1
Horned Slug - Chapter 10, The Mountain Troll, Layer 2
Mistletoe Berries - Chapter 12, Christmas at Hogwarts, Layer 3
Infusion of Wormwood - Chapter 12, Christmas at Hogwarts, Layer 2
Leaping Toadstool - Chapter 15, Into the Forbidden Forest, Layer 1
Unicorn Blood - Chapter 15, Into the Forbidden Forest, Layer 2
Bezoar - Chapter 17, The Hospital Wing, Layer 3 (Costs ~10 Galleons in Diagon Alley)
Salamander Blood - Chapter 17, The Hospital Wing, Layer 3

Chamber of Secrets Potion Ingredients:
Flower Heads - Chapter 1, The Magic Word, Layer 1
Honey - Chapter 1, The Magic Word, Layer 3
Dried Nettles - Chapter 1, Two Enourmous Green Eyes, Layer 3
Rose Thorns - Chapter 1, Two Enourmous Green Eyes, Layer 3
Horklump Juice - Chapter 2, The Weasleys', Layer 3
Dragon Liver - Chapter 4, Borgin and Burkes, Layer 3
Peppermint - Chapter 4, Lucious Malfoy, Layer 1
This list is incomplete, as the entirety of Book 2 is not yet available.