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

After an accident robs them of their parents, Rarity writes Sweetie Belle a letter laying bare a secret kept all the little unicorn's life.

"It's fascinating the level of depth this story takes. Just the part alone about why Rarity represents generosity is enough to bring tears to even the toughest critics. This is an amazing story in every way. Mature in some of its themes and true to life, yet not graphic or exploitive, 'Dear Sweetie Belle' is a must for My Little Pony fans who need a great, sad story to tide them over."
-Obake, Pony Fiction Archive

Beautiful cover-art by AcrylicDawn

A fantastic bit of fan-art from my dear friend Kaitlyn Warner.

A live reading by the Doom Pie Network Right Here

Princess Celestia was sure that the day was going to be great. The Sun shone bright in the sky, the birds were singing, and nothing could possibly go wrong. That was, until she received some rather grim news concerning her sister.

She thought she'd been clear enough about things last time.

Polish translation by Dolar84.
Spanish translation by SPANIARD KIWI.
Audio reading by Pony&Wolf Productions.

Trixie's line of work is dangerous. But she's a careful showpony, and that's why she's only died a few dozen times in her career.

She thinks this is normal.

Princess Celestia, tired of the constant pressure that ruling a nation puts on her, decides to take a day off and let Luna take her responsibilities for a day, something the younger alicorn is more than happy to do. She disguises herself as a pink maned pegasus pony named Sunny Skies and decides to go walking around Canterlot without any supervision. Unfortunately for her, not all parts of Canterlot are as safe as the palace, and she finds herself at the wrong end of a gang of muggers, who decide to kidnap her for a ransom when they see how much money she has on her.

Luna freaks out.

Celestia thinks it's hilarious.

Find this story and more in a print copy! Just click these words here!

Featured on Equestria Daily 8/15/13

Go here for the French translation!

[img]http://i.imgur.com/CUBPvKI.png[/img]

Edited wonderfully by sqarishoctagon and Cloud Hop

Updated cover art by Dominatore

These are the meditations of Princess Luna as she goes for a walk one cool, blustery, fall afternoon. There is sadness. There is happiness. There is complexity. It all seems so simple, because it really isn't.

After Rainbow Dash is sent to Cloudsdale High Boarding School she finds things a little trickier than she thought. Fortunately she meets a certain yellow filly who shares her love of music.

Projecting? Me? Never. this is a Flutterdash fic taking place in the filly years. (In this case meaning high school age.)

Teen rating just to be on the safe side in case of suggestive or naughty language, nothing major though.

This is my first fanfic so please be kind but if you notice any spelling or grammar mistakes please do tell me.

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.

Twilight Sparkle is an expert in unicorn magic, but earth pony magic remains a mystery to her. The books in her library have very little information about the earth tribe's abilities, other than their famous strength. Twilight is determined to uncover their secrets.

What she learns will change her life.

And it just might change Applejack's life as well.

Featured on Equestria Daily.

Prince Blueblood thought the Grand Galloping Gala was over. He thought he could just go to sleep and put it behind him. He never expected to be reliving the same disaster of a day, over and over... and over.

TV tropes page here:
http://tvtropes.org/pmwiki/pmwiki.php/FanFic/TheBestNightEver

Thanks to all the people who wrote the page and all the people who gave me a little wakeup call and comment to become aware of that fact! You can't see it, but you guys put a real smile on my face tonight.

Also, recently, extra thanks to RD Dash for giving TBNE a thorough editing. I've updated the fic accordingly (7.11.12)