Twilight and Rarity are just your ordinary mages from Ponyville. One enjoys fashion, while the other enjoys particle physics. But these girls are the best of friends, sharing many common interests with one another. So they delight in the task given to them by Princess Celestia to protect the Diamond Muffin from theft. Too bad they're vying to steal it for themselves.
That's right, Twilight and Rarity are burglars, and neither one knows it yet. But when they find out, will they try to stay friends, or finish the job first?

Art work by the awesome MrWestCoast. Be sure to check him out, mis amigos.

For a few months now, every Tuesday, a strange occurrence would bring a visitor to Equestria. Sometimes it was more than one. Some were friendly, and would come to cherish their time in the land of Harmony. Some were not so pleasant, driven by lust, greed, or wrath. They do not get to stay for long.

But the visitors of today were different. They did not come alone. Now it's up to Princess Twilight Sparkle and company to figure out not only what came through with their visitors, but how to stop it, before it stops them.

Just my take on many HiE fics and a spot of good humor towards the trope. Spoilers likely in the comments, so proceed at your own risk.

Just another glorious day in Ponyville, till the nanite infection is activated. Now it's up to Rarity and an infected Twilight to save the world. This will prove easier said than done though as old friends, enemies, and teachers come out of the wood work, and they all want to shut down the intrepid pair. But have n/ ...detgruhfihvdsivbhdsfh
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Insubordinate data terminated. Run Program: Imperium.

Credit for the cover pic goes to Thattagen of here and Deviant art. Be sure to like, fave, and follow.

Caught in the throes of an epic pony prank war, Twilight decides to use a new spell of hers to get even with a certain white mare. But one stop off to prank Rarity turns into a call for help, and a budding romance for the two unicorns, with a few feline perks. But Twilight should really have stopped with that spell long ago, because now she and Rarity face an enemy they never saw coming.

Edited and assisted by The Abyss Be sure to like, fave, and follow if you don't already.
Image was found on derpiboo.ru without source. If known, please let me know so I can give credit where credit is due.

The Nightmare has returned, using Rarity as her new vessel. Twilight steps up boldly to save her, but is soon lost to the darkness. What evils lie in wait for these two now? What horrors await the innocent in their path? Can they take over Equestria?

Not likely, seeing as it's still Twilight and Rarity, and despite the new looks, it's the same old ponies. A new romance between the pair does little to aid their conquest. Heck, it would take complete incompetence on the guards part and easily scared ponies to see these two in any real position of... power...

We're all doomed!

When a gossipy Rarity sets up the idea of using a spell to help her and Twilight find their true loves, they were biting off more than they could chew. Now these two mares will go to great lengths to change their destinies. But is all of that effort just spent spinning their wheels, or can Rarity and Twilight make their own destiny.

Story takes place between Games Ponies Play and Magical Mystery Cure.

Time Turner was the best. Simply put, the best. He was the greatest Doctor anypony could ever remember. But like all actors, eventually, he had to give up the limelight and go back to the real world, with his marefriend, Derpy Hooves. So sit a spell, and learn about the colt's times and trials on the set of Canterlot's greatest series, Doctor Whooves.

Just a random idea I had. Pic credit goes to DiasFox of http://diasfox.deviantart.com. Please support their works.

Edit 22 Apr 2013: Here is a random alternate ending I thought of last night at work. I liked it too much to let it go unwritten, so enjoy.

Rarity loves her classical tunes, but when her favorite record gets damaged, she needs a new one. A turn of fate sends Rarity home with Discord S&M (Metallica S&M to us). So now for the white fashionista, Let There Be Rock!

Pic credit goes to Jowybean on deviant art.
I saw this picture, and it made me wonder, 'How would Rarity come to love Rock? She's a classical mare...' What follows is my thoughts on that question, and I hope you enjoy.

After a severe magical storm hits Ponyville, the quaint village finds itself trapped inside of Twilight's books, acting out the stories. But the mane six don't care to follow the plot, they just want to go home. Of course, hilarity, randomness, romance, and Rarelight/ Spiknie/ Flutterpants and many more ensue, just because I can.

Edit: Finally got the source for the cover pic. Just follow the link to like, fave, follow.

Rarity has fallen hard for the lavender mare from Canterlot, but there is just one problem, that certain mare from Canterlot is completely oblivious to it all. Thus, Rarity does everything in her power to escape the dreaded friend zone, from skywriting to asking Twilight's parents for help. But will it be enough? Probably not. After all, Twilight is rather naive, but a mare's gotta try.

The pic that inspired this story, and the cover pic credit goes to ~SigneTheSlaske of Deviantart.com, check them out for more great artwork.