[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]

When Twilight and Celestia have an argument about the existence of leap years, there’s only one possible way to settle their differences: a race around the world!

With the full benefit of hindsight, there may have been other ways.

An 80 Days crossover, written as part of Horizon's writing challenge. Edited by Ether Echoes, Soge, Giant Hat, and Tormented Dragon, who are all amazing.

Lyra thinks Discord is an idiot for not thinking to dodge when the Elements of Harmony were about to strike him. Discord thinks this is the perfect opportunity for a game.

Part of the Borderworld.

Now with audio reading by Dreamless Portal. Chinese and Spanish translations also available.

Strange symbols have started appearing all across Equestria that nopony can read, except Discord. As he comes to grips with what this message means, he is determined that nopony find out its secret. If they do, absolutely everypony in Equestria will die.

This story is a cosmological crossover with The Three Body Problem trilogy by Cixin Liu, and thus contains spoilers for that universe. But can be read without prior knowledge of that story.

Audiobook available on YouTube!
Featured on Equestria Daily!

Celestia wakes up in human form and at an insane asylum where similarities between the world she is in now and the world of Equestria cause her to wonder if Equestria even exists or if she simply made it up to escape her human life. Does she try to hold on to her memories of her Canterlot life or does she let them go and accept them as nothing more than stories? Who is she going to trust? Who is she anyway?

This is only the beginning...

TV Tropes Page

Cover Art by blahblahaha123 (with some altering by me.)

Reading by Phantom Brony

Editors:

Csquared08, DarkPheonix, Gweat and Powaful Twixie, HenryAnthonyCourtler, Kaidan, KartalTheWriter,ZeroOmega

One beautiful morning, Twilight Sparkle decides she wants a free salad. After a small amount of theft, assault, battery, and arson, she sits down to enjoy what is sure to be the best tasting salad ever.

...Or she would have, if it weren’t for the Equestrian Intelligence Service locking her up as a potential threat to national security. Now, Twilight must escape a maximum security holding facility hidden deep underneath Canterlot. And to do it, she’ll need a paperclip, a spymare catsuit, an escape plan, and an alliance with the dastardly Drakbog, King of Frogs.

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.

Twilight isn't having a very good day. An experimental spell blew up in her face, an army of changelings is attacking Canterlot, and she just died. Yet somehow, it looks like it's going to keep going downhill from here.

Given the chance to correct what's gone wrong, Twilight swears she's going to fix all this even if it kills her. Which it will. Frequently.

Cover art by Pixel Prism
Spanish Translation
Series TV Tropes page

Crime was easy before Princess Twilight and the First Five ushered in a golden age of Harmony. Back then, any idiot could plan a robbery, just like any rat could sneak through the cracks in wooden granary walls. But now that everything is cloudstone and clearsteel, with magical countermeasures over the few remaining holes, it takes a different breed of rat to survive.

"Slippery" Jimmy the Grey is one of the rare few ponies who can still slip through the cracks — even with the legendary Rainbow Corps on his tail. Now he's got a billion-bit heist planned in the gleaming skyscrapers of Cloudsdale. If only he hadn't made the mistake of stealing from a dragon …

Now with a reading by Illya Leonov and Scribbler!

* * *

This is a crossover with Harry Harrison's Stainless Steel Rat novels, but it assumes no knowledge of the series.

Winner of February's Writeoff Association competition! * Featured by Equestria Daily! * Featured by Seattle's Angels!

REVIEWS: "Highly Recommended" by Titanium Dragon; "Recommended" by Present Perfect; rated "Why Haven't You Read This Yet?" by PaulAsaran

WORD OF MOUTH:
"The Iridescent Iron Rat was not only my favorite story from the most recent writeoff... it's my favorite story of anything I've read in months." —Sharp Spark

"What a ride it is. This story is made of awesome moments." —Casca, Seattle's Angels

"[A]stounding on so many levels. … If there’s one story from this round you have to pick, make it this one." —Corejo, Seattle's Angels

"Absolutely beautifully done. It fits the style and feel of the books to a perfect T." —Themaskedferret

There's a lot of things about Cadance and Shining Armor that never quite made sense: their sudden appearance before the Royal Wedding; their suspiciously convenient suitability as rulers of the Crystal Empire; their oddly abbreviated pregnancy; and even their quick change of heart after Spike asked them to forgive Thorax.

Twilight Sparkle knows exactly how deep that conspiracy goes — she was there in the beginning, when her hive's queen created Shining. And she wasn't happy about it.

Finalist in the "Things Left Unsaid" December 2015 Writeoff! Rewritten and greatly expanded to fill in more backstory and to account for Season 6 canon.

Rated 'Worth Reading' by Titanium Dragon! "If [you like] the idea of a story which hints at a greater conspiracy behind the scenes which explains some of the plot holes we see in the series, you’ll likely enjoy this."
Reviewed by Matthewl419!

Cover art by Lo-23, using Twilight from "Deception is Magic" by Heilos.