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

Princess Luna has got into an argument with her older sister and goes to her private realm to vent. Meanwhile, in another realm, Prince Artemis has got into a similar situation with his brother. From what was a simple meeting between alicorns of the night quickly becomes anything but simple.

Rated Teen due to language and subject mater.

Note everything below this line is not important to the story in itself as it has edits to the tags, my team of editors, and feature date list.

A big thank you to Foals Errands for getting me cover art so fast.

EDIT:

Got onto the popular list on the same day I posted this story, WOOOOOOOOOOOOOOOOOOOOOOOOT!

EDIT

06/23/2014
FEATURED!!!!!!!!!!!!

EDIT:

To list my crew of helpful friends, that help me keep this story coming out in a well timely pace.

Foals Errands, my friend and growing co-writer of my work.
Deepsleep64, my chief editor for this story, and hopeful more to come
Pure Note , my secondary editor
Ninja-PON3 , beta reader and one insane, but fun fan.
Lord Artemis, my second beta reader and good fan that offered his services
Noble Thought a person who helps out at times.
EDIT:

Tags changed

EDIT:

New co-writer is Anon the wonderful shark mouse and a TV Trope Page

http://tvtropes.org/pmwiki/pmwiki.php/FanFic/AChanceMeetingOfTwoMoons

Prince Artemis is faced with a conundrum. His brother, Solaris, seems to be contacting an alternate dimension through magical dreams, and covertly meeting with an Alicorn Princess that bears a striking resemblance to him. Inspection of this causes the lunar prince to run into somepony he never will forget... himself.

Rainbow Dash is grounded by a storm in Ponyville. She finds sanctuary within the library but Twilight Sparkle soon finds out that the storm isn't Rainbow's only problem. She's suffering from a very personal pegasus problem and Twilight has taken it upon herself to look after her friend during this delicate time.

In the far reaches of Canterlot Castle, high above in the towers lived the archmage. Everypony knew her, yet few had met her.

Twilight Sparkle sighed, having teleported away another noble seeking favors before reaching the top of the stairs for the second time today. They never learned. As the archmage, she already dealt with political squabbles far too often without inviting them into her home. Aside from personal favors for Celestia, she did what was required of her position and then returned to seclusion and research.

The nobility grumbled that no archmage should be a commoner, and Twilight’s disrespect toward them proved it. Each and every time they were forced to bow to her, they hated what they saw: the position, the status, the deference.

Was she not powerful? Was she not great?

Twilight, now reading through dusty scrolls and long forgotten tales, wrote in her notes — notes gathering dust of their own. A brief thought flashed through her mind.

Am I not powerful? Am I not great?

And then Twilight picked up The Tale of the Royal Pony Sisters.

Defunct side stories told in Across the Boundary. They can still provide a little context, but when in doubt, the main story here is canon.

Cover art provided by Lafiir

A few days after the Nightmare Moon Incident, Spike awakens to find Twilight acting a little...odd. Or odder than usual anyway. All of a sudden she's being all motherly, sure of herself in ways she's never been before, and even more outgoing.

But…it’s kind of creepy how she just seems to know everypony’s name, or their habits, and even some stuff nopony else should know.

But she's still good old Twilight...right?

Featured 5/28/2014

(REWRITE IN PROGRESS)

After a weekend spent in Canterlot, Twilight Sparkle arrives home to find an odd scroll in her saddlebags. In the following days Twilight is plagued by terrifying nightmares, and horrific visions from a life not her own. Can Twilight Sparkle resist the Nightmare, or will she fall prey to the darkness?