After a magical mishap renders Rarity temporarily blind, Twilight Sparkle agrees to help her around the Boutique, utilizing a fancy spell that allows Rarity to see a simple outline of the world around them. It's just a gesture of good friendship; absolutely nothing more.

Nothing more whatsoever.

Who: Monochromatic
When: Interwoven Colours Conest
Where: RariTwiGroup
Why: Panties

The guards are scared to say it.

Sunset Shimmer has returned to Canterlot.

And the Princess is furious...

Not in continuity with my other stories. Just something that popped into my head one day.

Spell Nexus (mentioned only) is from Past Sins, by Pen Stroke

Getting rejected by Sunset seems like a pretty good reason for Twilight to hole herself up in her room for three days. But when Rarity comes asking for help to develop a website for Carousel Boutique, Twilight can't ignore a friend.

Both of them may find they have something to learn about rejection, how to deal with it, and if a friendship really can become something more intimate.

An entry in Monochromatic's "Interwoven Colors" contest.
Cover art by Novel-Idea.

Centuries after most of her friends have all passed away, Twilight decides to make one last trip into the past. No interacting, no greeting deceased friends, no reunion with her beloved marefriend. Just one quick glance at a life long lost.

However, for better or worse, she'll end up getting much, much more than that.

This story has a prequel entitled The Last Train Home.
Cover art by Swan Song

After agreeing to Twilight's proposal of having a date in an alternate universe, Rarity finds herself contemplating many things, including but not limited to: what it means to be a human, how are you supposed to walk on two legs, meeting teenage versions of yourself and your friends, and last but not least, questioning your entire relationship and the nature of soulmates.

Going on an inter-dimensional date with her marefri—sorry, girlfriend—was not supposed to lead to the existential crisis of a lifetime, but there was Rarity anyway.

Set in the same continuity as "The Swap". Absolutely not set in the same continuity as "Your Own Worst Enemy".

Cover art by the wonderful Maxima.

When Twilight Sparkle slipped beneath the covers last night, everything had been fine. She had friends whom she loved, a teacher she adored, and a bright future ahead of her. But when she woke up, her blankets and quilts had been replaced by hospital gowns and padded restraints.

Everything is wrong and nothing makes sense; even her friends have changed. The doctors keep telling her that she is sick, that none of it was real and that it was all in her head. Yet she remembers a life far beyond the hospital walls. She couldn't have made it all up on her own. They must be lying… right?

Ask Asylum Twilight - Still updating regularly!
Equestria Daily
TVTropes
Asylum Fan Group
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The Asylum 20,000 View Spectacular Stage Show!

Art:
Asylum Cover by conicer
Twilight and Twilight Smiles by dreamingnoctis
Mirror Twilight and Plague Doctor by Jaestring / BloodGoldWings
Twilight Smiles and Doctor AJ by conicer
Nurse Ratchet and Silas and What's in the mirror? by Archonix
Doctor AJ Sketch by Archonix | Colored and vectored version by ReFro82
Twilight's Asylum by Khan the Cake Lover
Smilight by HappySwitch
Twilight Waking Up by Dombrus
Fan Art by toxicdemon10
Asylum Twilight by Madness-With-Reason
Asylum Fluttershy and Asylum Ch 26 by Downburst-Backspace
Twilight and her Twin by v747
Birdgirl by sirValter

Readings and Videos:
Asylum Animated Trailer Video by formuladash
Reading by Gammarobot (SugarCubeRadio): All Chapters Here
Reading by Ender Brony: All Chapters Here
Reading by VisualPony: All Chapters Here
Reading by MelancholyIguana: All Chapters Here
Fan Trailer by Kaidan: Asylum FanFic Trailer Cuckoo's Nest

Sanctuary by Kaidan
Broadhoof Files: Dr. Humors by TypewriterError
Broadhoof Files: Corporal Phalanx Spear (Ret.) by Phalanx Spear
A Hearth's Warming Tragedy by Seven Fates

A special thanks to Breath of Plagues, Rex Ivan,
ChudoJogurt, Cynewulf, Death the Kid, Selbi, PrinceDolph, Blahman2816, Queue, and Gage!

Axan Zenith - Dr. Dreamer
Dratini4 - Way Finder
psychicscubadiver - Bright Mind
Velkaden - Dream Chaser
Reese - Silver Glow
Viola Heartstrings - Clover
Archonix - Spinney Whiteacre

This story is a sequel to The Celestia Code

When the monsters created by the dark crystal engine escape their prison, it's up to Princess Twilight Sparkle to deal with them. She gets help and advice from Princess Luna, but things don't go as planned. In fact, when a pony who relies on logic and rationality tries to navigate the stormy seas of emotional entanglement while simultaneously saving Equestria from a horde of evil creatures intent on destroying everything they encounter, nothing goes as planned.
AUDIOBOOK by VisualPony
WARNING: Major spoilers in the comments.

Book 2 of the Alicorn Adventure series.

Goodreads Page
100% Approved by Twilight's Library!

The Badass Twilight tag applies more than ever, but please note the new tags.

This story is a fairly direct continuation of The Celestia Code. You might be able to follow it without having read The Celestia Code first, but it's better if you do.

The sequel is here: The Twilight Enigma

Most excellent pre-reading/editing done by the erudite AcademicPony and the dapper statoose!

Princess Twilight Sparkle discovers a centuries-old mystery hidden in the Royal Archives. Her investigation leads through layer after layer of deception and misdirection, setting her hooves on a path that seems to be leading to a mysterious secret. Along the way, she learns that some friendships can be very, very strange.

Book 1 of the Alicorn Adventure series.

AUDIOBOOK by VisualPony
Featured at the Royal Canterlot Library
TV Tropes Page (Courtesy of Sandtalon)
Goodreads Page (Courtesy of Facedeer)
Equestria Daily Page

WARNING: Major spoilers in the comments. Takes place several months after the end of season four. (Not a Da Vinci Code crossover, BTW!)

Do you see a dark tag? No, you don't. Not dark. Well, okay, there are a couple of dark-ish bits, but that's all. Not enough to warrant a tag. Speaking of tags, there really ought to be "Badass Twilight" and "Friendshipping" ones.

Sequels and side-stories (and more) can be found here Offprint and AO3, and a hardbound two-volume set of all that can be ordered from The Ministry of Image.

My editor for the first edition of this story was Gogito, and I can't thank him enough for all the hard work he did. My editor for the revised version was PresentPerfect, and he did a terrific job of getting the story into excellent shape.

As the world ends, a group of teenagers covered in blood enter Sugarcube Corner.

What follows is technically a love story.

Edited by Pearple Prose and Themaskedferret. Preread by Undome Tinwe, MaxKodan, and Majin Syeekoh.

An entry for Oroboro's Changing Seasons contest.

As the Princess of Friendship, the only thing Twilight Sparkle loves as much as books, reading, books, making new friends, books, spending time with her friends, and...books...

...is spreading the magic of friendship. And one easy way to do that is to introduce your friends to each other.

In need of a weekend away from the castle before heading out to the Crystal Empire to spend time with her family, Twilight decides to take a little vacation to the human world...and brings three of her newest friends along.

After all, if Princess Ember, Moondancer, and Starlight Glimmer are all Twilight's friends, surely they'll get along well with each other and with Sunset Shimmer!

Right?

(Cover compiled from various source vectors.)