After discovering that Cadence is not who she appears to be, Twilight is sent to another world entirely by the disguised Changeling Queen to avoid her plan being disrupted.
When Twilight lands, she discovers that not only have Spike, Owlowiscious and Peewee followed her, but that they've arrived in a world where the main sentient species is human.
There's still a place where they teach magic, though.
Crossover with Harry Potter. Twilight will be effectively taking the role of Hermione.

I've marked this story as cancelled to reflect the unlikelihood of it continuing. If I do come back to it I'll revert that.

Shortly after the Changeling Invasion, a human wakes up in Chrysalis' body in the middle of the Badlands. Alone, hurt, and starving, she tries to make sense of where she is and what happened. Unable to remember even her own name, she struggles with her identity as she faces the trials of being public enemy to a whole species.

Or, you know, she doesn't. Identity crises are overrated anyways.

Cadance has always loved Twilight, from the very moment the younger pony had entered her life. Lately, however, that love has evolved and blossomed into something altogether more. Will Cadance have the strength to confess her feelings to the oblivious Twilight? With two meddling aunts, she may not have a choice in the matter.

Cadance/Twilight. Twidance. Whatever you want to call it.

Shining Armour and Cadance have never been more than best friends. Set mid season 4. The Changeling invasion and Crystal Empire arc both happened, just differently. May flesh those out in a future oneshot.

Celestia has always watched over her little sister. When she has to banish her sister to the moon, she works to right some wrongs in Equestria so that her sister will be happier upon return.

However, the biggest change Celestia made has gone completely unnoticed by Luna since her return. Celestia calls Luna into her study to bring Luna's attention to one of the biggest changes of Luna's life.

(Note: romance tag NOT for princest.)

EDIT 3/26/14: In the popular stories box! Thank you all very much! This is my first really popular story, and I couldn't be more grateful for all the positive feedback!
EDIT 3/26/14 (again): Featured! Oh my GOD. This is just too awesome. I'm going to have a celebratory bowl of Lucky Charms and wonder how I came to earn the support of you lovely people.

Princess Celestia went out for a stroll to a coffee shop. The next morning, she is single-hoofedly destroying the coffee industry.

How?

No really, how?

This story is a sequel to The Moon Glows Gently

When you're the immortal ruler of an entire kingdom, the most important quality to possess is self-control. No princess can rule her nation if her emotions rule her. Celestia knows this better than anypony, and mastered them long ago.

So long ago, she may have forgotten that a little bit of passion can come in handy now and again.

Luna has a problem. She's spent all of her royal allowance, and she wants to go shopping! What's a mare to do? Ask her older sister of course! But when she is shot down for her own idea, Celestia decides that if Luna's going to get some extra bits, she's gotta earn it.

And so, Luna's going to have to clean out a vault filled to the brim with a thousand years worth of tributary gifts. Gifts she didn't ask for, or know she had, or even want! What will she do? Well, when you need bits, you do as the ponies do. Roll up your figurative sleeves and get to work!

(Based on a dream I had. Yeah, I'm a strange one.)

Persistent pesky powerful pony Princess pursues perturbed pretty purple pupil.

Alliteration is the least of Twilight's problems.

Winner of the Third Bimonthly Twilestia Contest.

Raising the sun isn't an easy job. Celestia knows that better than anypony. It requires vision and creativity, and she can only do her best work when the inspiration strikes her.

But, as is true with all good art, nobody else cares about that.

Rainbow Dash has never been to the eye-doctor. One afternoon Twilight takes her to the clinic to check her eyes after a minor flight accident. They end up finding out something that makes no sense whatsoever to any pony in Ponyville.

Woke up this morning to see that my random story that was published for no reason got featured 2/28/14. I'm not complaining, but it isn't a work of art :P. I guess anything a teenager writes about multicolored ponies amuses you.