Room of Requirement

"It is a room that a person can only enter when they have real need of it. Sometimes it is there, and sometimes it is not, but when it appears, it is always equipped for the seeker's needs"

—Dobby explaining to Harry Potter the abilities of the Room of Requirement [1]

The Room of Requirement is a secret room in Hogwarts, accessed on the seventh floor in the same corridor as a tapestry of Barnabas the Barmy teaching trolls ballet.

The Room changes to match the needs of whoever is in need of it, usually by a person in need wondering the hall at least three times with a desperate want. However there are limitations based on Gamps Law of Elemental Transfiguration

The Rules

• No Food can be created, nor can lifeforms be created that would become food. The only consumable is water or medicine.
• The Dead cannot come back to life.
• Objects placed within the Room can only be accessed via that mode of the room.
• However, if the room is creating things of a similar purpose, there may be recurring objects the Room creates.
• The Room cannot summon things that are not placed in the Room, it can only create or use what is stored in it.
• Everyone must leave the Room in order for a new mode to be accessed.
• If needed, secret passageways around the castle and grounds can be made.
• It cannot create books that haven't been previously written.
• Not even House Elves can access the Room unless they know what mode it is currently in.
• Any money produced will be seen as fake.

At Absit Omen

Given the use of the Room by the resisting students when Hogwarts was occupied by Death Eaters, the Room and its use is a little more prolific than it was in times past. However, a marginal majority may not know everything about the Room of Requirement right off the bat if they've never used it before.

Various modes of the Room have recurred on the site. See more at the forum board location

Room of Hidden Things (Ashen State)

During the Battle of Hogwarts the Room of Hidden things was subjected to Fiendfyre, magical flame capable of destroying almost anything. The spell was nullified when the Room was vacated and reset. Nearly everything that was placed in there previously was destroyed into ash. However, over the years as people continue to desperately need to hide things, unburned objects have become to populate the ashen mounds of the Room of Hidden Things.

Something Hidden in the Ash

Dojos and Training Spaces

Frequently students will develop their own dueling grounds. Common elements include training dummies, spell targets, and sandbags. Examples include:

Amara Báthory's workshop and training space

Demitria Strelnikov lets off some steam

Battle Club

At first glance, this is another example of a training ground but from subconscious experience the space used by Hexy is modeled after a nightclub (specifically Spellpunk). This large space features stained glass windows, magical lights, red couches set into the walls, a raised dance platform with tracks for training dummies, an empty minibar and an immense wireless/record player in the corner with an extensive record library and huge speakers. When the music starts the entire room animates the dummies, targets, and colored lights. Various graffiti that move about have been added to the walls.

Soulfire

Spell Fights

rough layout

Music Room

Students such as Demitria Strelnikov often retreat to a Room dominated by a Grand Piano, other instruments, and a small music library.

Broomstick Arena

A large enough Room to race brooms around. Painted lines circle the routes of the track with golden hoops to fly through.

He's a demon on whee--brooms

Dresses Dresses Everywhere

Always handy in a pinch when a wardrobe malfunction should ruin your school dance, the grandest closest of dresses and accessories can be found.

Cinderella Until Midnight

Another reference from Masquerade (half dress shop/half Battle Club)

A Dog Track

Sasha Schlagenweit developed a doggie obstacle course and play park for his trained companion dog Baldur.

The Weather Outside is Frightful

The "Infinite" Stage

During her tenure as Hogwarts Players president, Ligeia Canterbury researched Headmaster Dippet's ban on the Christmas Pantomime. Notes from Herbert Beery[2], the ill fated director, stated they rehearsed in a 'grand baroque theater that only appeared on Sundays.' It includes box seats and an orchestra pit. The stage has several backdrops & curtains, but you shouldn't pass the 9th curtain...

A Hall to Loose Yourself In