Celestia's morning has been difficult enough, between hearing Twilight's confession of love, and then breaking her heart as gently as possible. Mere moments later, her private chambers are rocked by the shockwaves of a time-traveling spell. This marks the arrival of Celestia's alleged lover from five thousand years in the future, Princess Twilight Sparkle—or as she insists on Celestia referring to her, Glitter-Flanks.

Armed with thousands of years of knowledge of which buttons to push and how to make her squirm, Glitter-Flanks has traveled back to this date for one singular purpose: to establish the closed time loop that sets the two of them up as a couple.

"You can be anything you want to be," the teacher explained, "so long as it relates to your name or cutie mark." Such is the life of Mayor Mayor, doomed to become the mayor of the demented town of ponyville. How do you escape a fate that's already determined for you?

Deep in the Royal Library is a book. A terrible book that is said to send whoever reads it mad. A book so dangerous that it has to be hidden away and secured with chains to prevent it from ever being opened.

A book which has just been accidently checked out by Spike on behalf of Twilight Sparkle.

The Star In Yellow is rising once more, and only Rainbow Dash and Spike can save Twilight before it's too late. Ideas live forever. Ponies do not.

This fic is loosely inspired by the 19th century story 'The King In Yellow'.

In a dark place named Tartarus, a subterranean hellscape between worlds, humans and ponies are paired together at random to survive a gauntlet of horrible monstrocities while the future of their realms hang in the balance.

Now, are you buying that? Good. Cuz I'm friggin' tired of having to explain it all on top of dragging this annoying-ass unicorn around the effing corridors of purgatory along with me. You'd think the damn, burning yahoos who run this place would give us rest stops to drown ourselves in beer or something. Friggin' A.

Oh, and some ponies and humans spill blood together and stuff. I dunno. Stop playing BattleDuty: Future Football and read this, or whatever. Like I give a crap...

When the Cutie Mark Crusaders dig up an ancient magical artifact, they unleash a spell on the town that allows everypony to see a "lie meter" floating above each other's heads. While attempting to solve the mystery, Twilight Sparkle has to analyze the tenuous balance between friendship and honesty. She doesn't like what she finds.

Based on a story idea conceived by theworstwriter
Written and posted with his permission

The common household Sweetie Belle has many uses and applications. Here are a few of them.

This is a fic based on the Time Loop Files, the format of which was first codified by Innortal on fanfiction.net.
Here's a brief guide.
The basic idea is, one character (the Anchor, usually the main character of a fictional setting) is looping back to the very first moments of their parent series every time either they die or some kind of time limit expires. They of course end up monumentally stir crazy given enough time.
Eventually others start to loop as well.
The reset is not always perfect. Sometimes a loop's history will be different to the "prime" loop, or canonical plot.
"Crossover" or "Fusion" loops also occur, randomly. These can involve the home loopers having a guest, or the anchor for one universe spending time in another, or replacements of one character by another.
Vacation Loops are where the Anchor (or others) decide/s "buck it" and lets off steam by doing whatever comes to mind. There's little or no attempt to maintain the original timeline.

In addition, and particularly more recently, it should be known that this story has a collaborative element to it - people may submit loop ideas or loops, ideally at the Spacebattles thread (a link to the current version of which is on the Trope page), and they may become included.

There's two page image options, thanks to Filraen - the current page image has been edited by the original creator from this work of theirs.. The other one is here:
http://hourglass-vectors.deviantart.com/art/MLP-Loops-466030169