The Ballad of Twilight Sparkle

The Ballad of Twilight Sparkle is a romantic comedy fanfic for My Little Pony Friendship Is Magic.

The story starts on a typical day in Ponyville, aside from the fact that Twilight Sparkle is recovering from a big hangover. Oh, and she's just been called away to Manehattan to talk with the Great and Powerful Trixie (who Twilight had been searching for ever since her dramatic departure from Ponyville) and the folks at Metro-Goldwyn-Brayer about a movie Trixie is making... about Twilight. Meanwhile, Rainbow Dash is hiding in Twilight's cupboard from Applejack after their night of drunken revelry got a little out of hoof, Rarity is running around dressed like a warrior mare, Spike is worried for his friend/big sister figure, Fluttershy is dodging the paparazzi again, and Pinkie Pie is... well, Pinkie Pie, only moreso.

So perhaps it's not such a typical day in Ponyville after all.

Hilarity, misunderstandings, romance, legal complications, and other craziness ensues as Twilight is dragged into the wild world of show business... as well as a budding relationship with Trixie.

Tropes:
"Rarity was slightly miffed—not jealous, for that would be unladylike—at the fact that Rainbow Dash had gotten a better education than her!"
 * Almighty Janitor: Dash has not only gotten training as a Lawyer, but events seem to indicate that she could be a really good one. And she took a job as a weather pony.

"Opinion seemed split: half of the police force thought the two investigators were only stopping briefly in Canterlot before continuing their journey straight to the Moon; the other half believed that the sheer atomic weight of Flat-Hoof and Horseshoe's solid plutonium reproductive organs would make escape velocity all but impossible."
 * Baleful Polymorph: Twilight and Trixie accidentally turn a member of the pony paparazzi into a potted plant, and turn another reporter's mane into a bouquet of roses that shoot off fireworks.
 * Ballad of X: The Title.
 * Beta Couple: Applejack and Rainbow Dash.
 * Brass Balls: The opinion of everyone at the NYPD regarding Det. Gummy Horseshoes and Officer Bobby Flathoof when they request an audience with Princess Celestia about Rarity using her balloon to get into Canterlot. As part of a criminal investigation which could result in naming the Princess as an accomplice.

"Twilight Sparkle: Hey, what happened to your illeism? Trixie: My what?!"
 * Bread, Eggs, Breaded Eggs: Rainbow Dash mocks Miss Spelling by calling her Four-Eyes, then Butt-Face, then Four-Butt-Eyes-Face.
 * Calling Me a Logarithm:
 * When Trixie briefly drops her habit of referring to herself in the third person, the following exchange occurs:

"Twilight: I swear, this has never happened to me before!"
 * Trixie has a similar reaction to Twilight calling Princess Celestia a "polymath" in chapter 14, as does Applejack.
 * Charm Person: What Rarity thinks may be going on with Twilight and Trixie to justify her friend's interest. Interestingly, Rarity seems to imply that she's done so herself in the past, albeit as something she regrets to this day.
 * Chaste Hero: Twilight Sparkle is more clueless about romance than she ever was about friendship.
 * Continuity Nod: Fluttershy is pestered by a horde of paparazzi ponies who recognize her from her modeling career in "Green Isn't Your Color". Later, she makes use of Pinkie Pie's hay-bale disguise from "Party of One".
 * Cry Cute: Trixie, after being subjected to The Stare.
 * Date Peepers: First Fluttershy and Pinkie Pie (with a reluctant Trixie in tow) eavesdrop on Applejack and Rainbow Dash confessing their feelings. Then Pinkie, Fluttershy, and Applejack follow Trixie and Twilight around on their first date (though Twilight insists it's Not a Date).
 * Death Glare: Apparently, Fluttershy's "The Stare" works on ponies as well. Trixie gets a close-range full-strength one, and it reduced her to a terrified, sobbing wreck.
 * Determinator: Trixie wants to learn Twilight's teleporting spell, but it being instinctual to Twilight and her alone, there is absolutely nothing recorded on how to reproduce the spell.
 * Does This Remind You of Anything?: Twilight suffers a public "premature casting" during her reunion with Trixie.

"Stupid sexy Reinstein!"
 * Drinking Contest: Between Fluttershy and Big Macintosh.
 * Everypony Can See It: Pinkie Pie claims that everyone in Ponyville's been waiting for Applejack and Rainbow Dash to admit their mutual crushes on each other. Twilight and Trixie's feelings are apparently equally transparent.
 * Exact Words: In chapter 13, Spike points out that everypony promised not to follow Trixie on her date with Twilight Sparkle. The others respond that they're not following Trixie, they're following Twilight.
 * Face Doodling: Spike ends up on the receiving end of this in chapter 9.
 * Field of Blades: Rarity conjures one up while trying to pass off the weapons she confiscated from the Cutie Mark Crusader Dragon-Slayers as a new fashion statement.
 * Five-Man Band: Twilight's 'entourage' as Dash claims
 * Dash - Legal Counsel
 * Pinkie Pie - Event Coordinator
 * Applejack - Caterer
 * Rarity - Stylist
 * Fluttershy - Animal Handler (on account of Twilight's 'Dragon Pet Thing')
 * Spike - The 'Dragon Pet Thing'
 * Geeky Turn On: "[Twilight] always did get a bit worked up by relativistic equations."

"Applejack: 'Is that a fashion statement or a declaration of war?'"
 * Hidden Depths: Who would have guessed Rainbow Dash was a legal expert on the side?
 * She's also rather sensitive, given how she acts when she thinks Applejack just used her for a one night stand. It certainly makes sense the Element of Loyalty would take that badly.
 * Also quite the surprise that a timid and gentle pegasus would have such a tolerance for hard liqour.
 * I Have This Friend: Twilight tries to pull this on a librarian at the Manehatten Public Library while looking for advice on romance. The librarian sees right through it.
 * Insane Troll Logic: Pinkie's "explanation" for why Fluttershy is wearing her hay bale disguise. Of course, seeing as it's Pinkie we're talking about, it's to be expected.
 * Intelligence Equals Isolation: Trixie seems to see this as the cause of Twilight's tendency to fall into Magi Babble around her at the slightest provocation. As Twilight is simply that much smarter than the rest of the Mane Six, the girls can't keep up and tend to tune Twilight out rather than try to understand her discussions on magic. Trixie, on the other hand, is possibly the first person Twilight's met since Celestia that could discuss magic with her on her own level.
 * Jail Bake: In Chapter 15, poor Ditzy Doo gets caught by the cops trying to deliver a cake from the Cutie Mark Crusaders, one with a file and a blowtorch in it, to Rarity.
 * Last-Second Word Swap: On arriving at the Manehatten Public Library, Twilight starts to ask for books on the study of love, but realizes that would be far too embarrassing with Trixie around, and ends up asking for books on "long-distance teleportation" instead.
 * Magi Babble: Twilight does this all the time around Trixie, from going on an extended tirade about how Pinkie Pie can't cast magic, to explaining five separate theories from physics in the course of attempting to explain how her teleport spell works.
 * Mythology Gag: The Cutie Mark Crusaders' brief attempt to get dragon-slayer cutie marks by going after Spike is a reference to the G1 My Little Pony episode "The Would-be Dragonslayer" in which G1 Spike was briefly in a similar plight.
 * Narcissist: Trixie's defining trait, obviously, but used to highlight her growing attraction to Twilight in Chapter 15, when Trixie realizes that the last Cutie Mark she'd spent so much time studying before Twilight's was her own in the mirror.
 * Not What It Looks Like: Rainbow Dash accuses Trixie and Miss Spelling of trying to brow-beat Twilight into signing over the rights to her name for Trixie's movie. It certainly looks bad, but Twilight leaves in distress before they can explain their intentions.
 * This seems to happen a lot in this story. In Chapter 4, after a drunken fling between Applejack and Rainbow Dash, Dash is upset when she overhears Applejack tell Rarity to let Rainbow Dash know she's "not that kind of mare." 5 chapters later, it turns out that AJ was talking in terms of chivalry, not sexuality.
 * Rarity's Shield-Maiden Chic draws a lot of this. The only one who doesn't react negatively is Spike, who's thinking something else.


 * Pass the Popcorn: Pinkie Pie watching Trixie and Twilight argue in chapter 14.
 * Perp Sweating: Attempted and failed by the NYPD with regards to Ditzy Doo. Ditzy is just too random for the usual tactics to work, on top of her being somewhat Genre Savvy due to watching a lot of cop shows.
 * Punny Name: Including Pegasus pilot Holly Diver and corporate lawyer Miss Spelling.
 * Shout-Out:
 * In the first chapter, Twilight is writing a letter to Celestia that ends "...and that's how I learned to stop worrying, and love the Bomb," though in her case she's talking about Jägerbombs.
 * Rarity may or may not have recreated Unlimited Blade Works in chapter 4.
 * When acting as Twilight's legal counsel, Rainbow Dash's first action is to interrupt Miss Spelling by slamming her hooves onto the tabletop and shouting "OBJECTION!"
 * While Pinkie Pie, Fluttershy, and Spike are on their way to the Clydester Building, Pinkie sings a parody of The Rolling Stones' "Paint It Black".
 * While flying around Manehattan, Rainbow Dash accidentally draws attention to herself by generating a "double rainbow".
 * At one point, Pinkie Pie dresses like Sam Fischer while sneaking up on a security guard keeping her friends from eavesdropping on AJ and Dash.
 * In Chapter 11, when Rainbow Dash is consulting a Rarity under arrest and about to be interrogated, she asks whether Rarity joined "an underground rodeo club that meets every week 'just to duke it out because you all feel disenfranchised and alienated by society?"
 * Show Within a Show: Trixie's movie, "The Brave and Beautiful Glitter Dawn". As Applejack jokes, "instead of writin' a love letter or sendin' [Twilight] flowers, ya'll wrote her a love movie?"
 * Springtime for Hitler: Miss Spelling accuses the studio of trying to bury Trixie's movie so it fails and they can exploit a tax loophole.
 * Tastes Like Purple: Twilight remarks to herself that teleportation makes everything "taste blue for a while afterward".
 * Title Drop: "The Ballad of Twilight Sparkle" is the name of Trixie's new roadshow, the one that inspired the movie which forms the basis of the plot.
 * The Un-Reveal: In chapter 10, Rainbow Dash hints that Trixie is just a stage name, but is quickly hushed by Trixie before she can say her real name out loud (it starts with a "B", but that's all we know as of chapter 13).
 * The Other Wiki states that (at least among us humans) "Trixie" is a shortened/diminutive of.
 * Those Two Ponies: More or less what Pinkie Pie and Fluttershy have been relegated to.