The Citadel

GRRM = George R. R. Martin
ASoIaF = A Song of Ice and Fire

AGoT = A Game of Thrones
ACoK = A Clash of Kings
ASoS = A Storm of Swords
AFfC = A Feast for Crows
ADwD = A Dance with Dragons
TWoW = The Winds of Winter
ADoS = A Dream of Spring

BotD = "Blood of the Dragon"
PotD = "Path of the Dragon"
AotK = "Arms of the Kraken"

THK = "The Hedge Knight"
TSS = "The Sworn Sword"
TMK = "The Mystery Knight"

TPatQ = "The Princess and the Queen"
TRP = "The Rogue Prince"

TLoIaF = The Lands of Ice and Fire
TWoIaF = The World of Ice and Fire

BwB = Brotherhood without Banners

The Brotherhood without Banners fanclub, named after Lord Beric’s merry band, is the nascent fan organization that has helped bring about such events such as a number of great parties during European and North American conventions. The BwB can always be found at the Brotherhood without Banners forum on the A Song of Ice and Fire board, so feel free to drop by and peruse the latest discussions. If you need to get in touch with the BwB, try PMing stegoking on the forum.

Mr. Martin does not approve of or allow A Song of Ice and Fire fan fiction.

Mr. Martin does not approve of people starting A Song of Ice and Fire MUDs or MUSHes without first obtaining permission from him to do so. Currently only one such game is approved: Blood of Dragons MUSH. Excerpts from relevant e-mails regarding the approval can be found at the Blood of Dragons MUSH FAQ.

There are many, many references to other works, authors, and media in the course of the series; there are even sports references. There are too many to readily list, but below are a handful of examples:

• House Jordayne of the Tor refers to the late fantasy author Robert Jordan, whose Wheel of Time series is published by Tor. In a similar vein, an Archmaester Rigney who alleged that history is a wheel refers to the series and its author again, this time using Jordan’s actual name, James Rigney.
• House Vance of Atranta and House Vance of Wayfarer’s Rest, including blind Lord Vance, and various kinsmen including Ronald the Bad, Hugo, Ellery, and Kirth, as well as the arms, all refer to the works of science fiction and fantasy grandmaster Jack Vance, who Martin considers the greatest living science fiction author. Vance has grown blind with age, and the various kinsmen refers to his works in some fahion: the novel Bad Ronald, the Hugo Awards which Vance has won, the fact that Vance was among the writers who used the Ellery Queen pen name, and Kirth refers to the protagonist of the Demon Princes series. Lord Karyl’s children are also references:  Emphyria (referencing Emphyrio), Rhialta (another reference to the The Dying Earth sequence, specifically the novel Rhialto the Marvellous), and Liane (a character from The Dying Earth). Wayfarer’s Rest also refers to Vance’s seminal fantasy The Dying Earth, as the character of Liane is known as Liane the Wayfarer; the arms with the eyes within a golden ring refer to the same story, and the dragons refer to Vance’s classic “The Dragon Masters”. The towers may refer to another classic Vance story, “The Last Castle”.
• The Drowned God and the words “What is dead may never die,” as well as the name of one of the past Greyjoy lords—Lord Dagon—appear to be references to the horror writing of H.P. Lovecraft (“That is not dead which can eternal lie,/ And with strange aeons even death may die.”).
• The Three Stooges (Larry, Curly, and Mo) were worked into A Game of Thrones, in the characters of the Bracken men-at-arms Lharys, Kurleket, and Mohar.
• The Volantene patriot and Triarch Belicho whose unbroken string of victories were allegedly put to an end by giants, who tore him limb from limb, refers to the 2007-2007 New England Patriots and their coach Bill Belichick. The team had managed a perfect season—the first team to go without a single regular season loss since 1972—and entered the Superbowl as heavy favorites against the New York Giants… only for the Giants to win. Martin is a a dyed-in-the-wool supporter of the Giants, and has been quite vocal when it comes to Belichick and the rivalry against the Patriots.
• In a similar vein to the above, Ser Patrek of King’s Mountain is a reference to book blogger Patrick St. Denis, who won a football wager with Martin after his Dallas Cowboys had a better season than the New York Giants. The knight’s arms feature a blue star on silver, a clear reference to the Cowboys dress. His death at the ends of the giant Wun Wun has been confirmed as a winking nod to a past New York Giants quarterback, Phil Simms, whose jersey number 11 was retired by the giants in 1995.
• ”... black hood, blue beetle, and green arrow”: A reference to comic books, specifically the Archie comics superhero the Black Hood and the DC Comics heroes Blue Beetle and Green Arrow. A variation on this appeared where the black hood was replaced by thunderbolts, which has been speculated to be a reference to the DC Characters the Flash (who is, with the Blue Beetle and Green Arrow, a member of the Justice League of America) and/or Johnny Thunderbolt of the Justice Society of America. Martin has been a comic book fan from early in life.
• House Willum features Lord Willum’s sons named Josua and Elyas, who are described as quarrelsome.. The reference is to Tad Williams and his “Memory, Sorrow, and Thorn” epic fantasy series, which feature (in part) the feuding royal brothers Josua and Elias. The arms of the house refer to the magical swords that play an important part of the story, and to the first novel The Dragonbone Chair. GRRM has cited the series as a major reason for why he went forward with “A Song of Ice and Fire”.
• House Costayne of Three Towers references the work of Thomas B. Costain, A reference to a Thomas B. Costain, a favorite historical fiction writer of Martin’s. The arms refer to the novel The Silver Chalice and the film The Black Rose (which was baed on Costain’s work).
• Harry Sawyer and Robin Potter are two mock suitors of Brienne the Beauty who paid for their humiliation of her at the melee in Bitterbridge. She recalls unhorsing Harry Sawyer and then mentions having given Robin Potter a nasty scar on his head. Some intrepid readers speculate that the close proximity of the names, and the scar Potter received, is a reference to J.K. Rowling’s Harry Potter, who has a distinguishing scar on his forehead.
• Ser Courtenay Greenhill is a knight who pays court to Margaery Tyrell. His names refer to two makers of to knights (which GRRM collects), Richard Courtenay and Peter Greenhill.
• Alaric of Eysen is described as a far-travelled singer in the books. The character is a reference to Phyllis Eisenstein’s heroic minstrel character Alaric.
• The ship captained by Lord Baelor Blacktyde, Nightflyer, refers to an award-winning novella by GRRM, “Nightflyers”.
• Bakkalon, the Pale Child is a foreign god mentioned among those with idols at the House of Black and White. This references a god of the same name that features heavily in Martin’s science fiction story “And Seven Times Never Kill Man” and mentioned in several other tales set in GRRM’s future history.
• The Fever River,  whose source is in the Neck,  is named after the river Fevre which gave GRRM’s novel, Fevre Dream, its name.
• Lord Titus Peake, a Lannister bannerman, is a reference to Mervyn Peake and his seminal work of fantasy,  the Gormenghast trilogy, starting with Titus Groan.
• House Wyl of Wyl features a black adder on its arms. Martin has confirmed that this is a nod to the BBC historical comedy series starring Rowan Atkinson, Blackadder.

Many more speculations as to references and homages in the series can be found at the A Song of Ice and Fire Forum thread devoted to the topic.