In the 14th novel of The Dresden Files, Harry must navigate the trickery and treachery of the Winter Court, re-connect with his allies, and preserve the secret of Demonreach Island against an insidious enemy ... and that's just on his first day on the job as Winter Knight! Amazingly, he manages to fit a record-setting number of Shout Outs in alongside the non-stop magic and mayhem.
In the first chapter, Mab tells Harry that she will most likely kill him in the morning. Harry assumes she was making an intentional reference, but it turns out she was being literal.
Butters apparently calls the swivel-chair in front of his main home computer the "captain's chair". He coordinates raids for (unspecified) MMORPGs from there.
Harry paraphrases Robert Frost's "Fire and Ice" - "To say that for destruction ice, Is also great, And would suffice."
"Feets, don't fail me now" is a line from classic vaudeville.
Another Yeats reference, when Bob calls Harry the embodiment of "Things fall apart".
Personally, he's more inclined to think of himself as Charlie Brown.
"The impossible we do immediately. The unimaginable takes a little while" paraphrases the motto of the U.S. Army Corp of Engineers.
Harry gets off a sinking barge as fast as he can, not wanting to get Titanicked.
Figuratively, he does at the end, when Murphy says that a relationship between him and her would be a Titanic in the making.
Also, how did Harry summon up an iceberg? By saying "Rexus Mundi," bastardized Latin for "I'm the king of the world!"
The cursed blade which Lea acquired in Grave Peril is referred to as "Morgana's athame" by Mab.
Thomas's "The path of excess leads to the palace of wisdom" paraphrases William Blake.
According to Harry, the Winterfae thought the Saw movies were hilarious.
Thomas owns a brass telescope, and claims they've been very popular items since those pirate movies came out.
Harry hopes his clothes will stay intact when he passes through a destructive ward, the way Superman's costume gets to borrow his invulnerability. In any case, he didn't have time to play Mr. Rogers and take off any clothes.
Toot-toot's latest set of armor is made out of Coke cans, including a shield sporting Coca-Cola's seasonal polar bears.
Harry has kept up with new music during his convalescence with the Unseelie Court: he mentions the Foo Fighters "Walk" as a choice for a montage of his physical therapy/attempted murder sessions, and dances with Mab to a symphonic rendition of "45" by Shinedown.
He sings a line from "Just A Gigolo" when he dons a tux; it's unclear if he's remembering Bing Crosby's version from when he danced ballroom at retirement homes or the David Lee Roth cover from his own adolescence, however.
Bob encourages Harry to trust no one. "Did The X-Files teach you nothing?"
Some hot female Sidhe are described as "a wood chipper in Playboy bunny clothing."
Jim Butcher even shouts out to another of his works: at Dresden's surprise party, Maeve has the same hairstyle as Kitai.
Harry, of course, hasn't read Codex Alera, so he compares her hair-to-one-side look to 1940s actress Veronica Lake.
As this is the third or fourth time Andi's been abducted, it's proposed that they start calling her Danger-Prone Daphne.
Harry refers to Mab's daily attempts to kill him as "Grimtooth games". Grimtooth's Traps is a series of system-neutral tabletop gaming supplements depicting all sorts of fiendish death traps, for use in fantasy and other settings.
Several references indicate that Tam Lin, like Dracula or the Necronomicon, has a factual basis in the Dresdenverse.
"Two plus two is five" is a 1984 reference. In Orwell's novel, it represents the State's ability to impose a belief that any lie — even statements innately-contrary to the mathematics of reality — is truth. In Butcher's, it's how Nemesis-infected Maeve declares that she can lie, regardless of how much it contradicts what is real.