When Princess Celestia comes down with a mysterious illness despite her immortality, her loved ones flock to her side, including Sunset Shimmer. With only so much time left, Sunset takes it upon herself and Twilight to get to the bottom of it. The two of them work together non-stop to find a cure, which would be fine, if Sunset had gotten around to telling any of them she's dating the other world's Twilight.

Edited by the kind and insightful Space Jazz. Cover art designed by the incredibly talented Kiki-Kit and modified by the masterful Amber Spark! Spoilers in the comments.

[Complete! With TVTropes apparently!]
Also, apparently, an animated trailer.

In a world of brass and steam, Twilight Sparkle had thought she had made a life-changing discovery with the invention of the telescope. For better or worse, she was correct.

Now her discovery has not only changed her life, but the lives of those she seeks out in her desperate attempt to contact the only other creature as lonely as Twilight herself.

It all would have been much simpler, but it had to be the one Twilight could only call The Mare on the Moon.

Decidedly not within walking distance, then.

[Featured on EQD before story was meant to be submitted. 4/03/2015]

[Editing team: Southpaw, Wolfvenom, Maskedferret, SwanSong and BluePaladin42, without whom this story would be a fraction of its current state.]
[Special thanks to Novel-Idea for the updated cover]

  After Sunset Shimmer brings Sci-Twi’s strange magic-absorbing amulet back to Equestria, Princess Twilight Sparkle has a brilliant idea. If they combine the amulet and the magic of the portal, the two of them could hop between worlds at the push of a button!
  Who better to test out this fantastic new technology than two of the greatest minds in all of Equestria?
  They probably should have calibrated it first.

SunLight Sliders is the result of the Sunset Shimmer community's epic three-month collaboration project, where each author had three days to write a 500-1500 chapter in the ongoing saga of Sunset and Twilight Voyaging through the multiverse! Every author picks up where the last one left off... giving us one crazy journey in space and time!

Featuring the Talents of:
Novel Idea
NotSoWickedWitch
Tumbleweed
DrakeyC
Fuzzyfurvert
RQK
Marwile
TheNewYorkBrony
Sunsette
Oroboro
OddOneOut
Tchernobog
KalenNighteyes
Idsertian
ratedoni
Space Jazz
The Albinocorn
CoverArt
SciSetDaily/Little-Tweenframes
Dubs Rewatcher
Deathscar
EbonQuill
journcy
X3n0heart
RadiantBeam

Cover Art by the Astoundingly Amazingly Awesome SciSetDaily
Cover Text & Section Break Design by Novel Idea
Twilight Sparkle Cutie Mark by Intbrony
Sunset Shimmer Cutie Mark By Millennial Dan

Editor Credits
Novel Idea - Lead Editor & Project Organizer
Ebon Quill - Audio Director & Quest Designer on The Manehattan Project
Little Tinker - Master of Systems at Poniverse & Scripting Engineer on The Manehattan Project
Beltorn - Commenter-at-Large on FimFiction

Special Thanks
To the entire Sunset Shimmer Group and all the commenters who embraced the madness of this crazy journey!
Tchernobog for constantly answering Novel's annoying questions about this exercise in lunacy.
The AppleDash Group for "At the Drop of a Hat" the original inspiration for this project!
Fahrenheit for his invaluable assistance in wordsmithing that fantastic synopsis and elevator pitch!

Word Count: 41,000
Version: 10.5

Dinky leads a double life. In the real world she is an average pony in her final year of school, slightly timid, bored with everything around her. In the Dream-Web she is a hacker who wants to make a name for herself.

One evening she stumbles on something that has both her lives merge in one, as she seeks to find whether the Web really is run by deities, or is this just a trick by the Starswirl Conglomerate.

Marked AU because of season 5 episode 18 - Crusaders of the Lost Mark.

Written for the F*** this prompt 6 competition

Special thanks to Malefactory and Elric of Melnipony for advice, editing and proofreading.

My roommate's name is Octavia, or "Tavi" for short. She likes vintage red wine, soft pillows, and long walks on the beach. But, more than anything, she loves music. She loves it with a passion that radiates with every burning color of the spectrum.

Each day I spend with her... or without her, I learn a little bit more about life, about the sick beat to which we all dance, whether we know it or not. I hope you don't mind if I say a few things about her. Just a few things. One can learn a lot from Tavi.

After all, she saved my life.

Cover Art by Eztp

Playlist - Because Even Original Things Aren't Original

When Gaberdine is awarded a noble title by Princess Celestia, he soon finds out that his new lands contain several surprises. For starters, there is no land in his new barony. Secondly, his new castle turns out to be a broken-down riverboat. And third is… seaponies.

Baron Gaberdine has a lot to learn about his new barony. And himself.

Fortunately, he has a very young teacher.

Now with a sea-quill (sorry) Drifting Down the Lazy River

Cover photo by PhoenixSwift
Editing/Pre-Reading assistance by Tek, Shaleclaw, Peter, Seether00, Monsieur Connoisseur, GhostOfHeraclitus, The Masked Ferret, Blue Paladin42 and Admiral Biscuit

Note: Unlike The Traveling Tutor and the Librarian, this is a single POV love story, like Changelings, Love and Lollipops. Only with fewer cannons and fountains.
Now Featured on Equestria Daily
With a YouTube Reading of the first chapter by BigAsh
And with a dramatic reading by Neighrator Pony and company Full playlist here.
Thanks for a wonderful review by Paul Asaran
Available in paperback through Lulu.com at cost.

When Twilight Sparkle was just a kid, her best friend was a girl named Sunset Shimmer. Though their friendship had a bit of a rocky start, they quickly became inseparable, no matter how much everyone thought of them as ‘weird’. They were there for each other.

Were.

Years after the tragic accident that tore them apart, Twilight is determined to move on from her loss, and she sets off on an independent research project to investigate the strange happenings at Canterlot High. Little does she know that she will soon come face to face with what appears to be a literal ghost from her past.

Coverart by Kare-Valgon. Chapter illustrations by Zorbitas.

Edited and Pre-read by Dubs Rewatcher, r5h, and Kalan.

Takes place after Rainbow Rocks, but was written before Friendship Games and does not take it into account.

Chinese translation

Print copies now available.

It's been two and a half years since Twilight Sparkle returned from the other world, leaving Sunset Shimmer in the company of the alternate group of friends she made. However, not all has gone well for her one-time rival in the other world. On the night of the 30th moon, Sunset emerges from the mirror and uses an ancient relic to switch their bodies. Alone in the care of Sunset's overbearing ex-tutor, Twilight uncovers the forgotten past that drove her rival to such desperation, while back in Ponyville, Sunset struggles with Twilight's lifestyle clashing with her own dreams.

Proofreaders: RTStephens, Winter Solstice, The Albinocorn, Dartrunner and NightWolf289.
Cover art: FallingRain22

Featured by Twilight's Library September 2014.
Featured on Equestria Daily