Mood Wings - Observations on Pegasus Body Language.

When Twilight Sparkle finds this book, she discovers an entirely new field of research. The secrets of pegasus wings lie before her, and she insists on making her own observations on the matter.

How?

Field research, of course.

It has been ten years since the defeat of the Changling Queen, and Equestria is again at peace. Twilight Sparkle and the Elements of Harmony have reached their prime, and have begun to settle down. Love and life abound in Ponyville, especially for Twilight's friends, but she has nopony to call her own.

There is a reason.

A series of events lead to a horrible revelation, and Twilight is thrust deep into a terrifying web of secrets and lies. Her peace is over.

This time, however, she won't be fighting monsters or madponies. What she faces will be much, much worse.

Act One of Two.

Act Two is here.

Currently undergoing editing by the wonderful Mstar!

After nearly being mugged Twilight turns her considerable talent with magic towards self defense. When a fight with Luna goes farther that either of them wants it to, Twilight will need to find redemption in her new position as Luna's bodyguard and stop a conspiracy that wants to bring back a force more dangerous than either of them.

Twilight Sparkle prides herself on following and sticking to her plans, but she isn't as organized as everypony thinks. Her master list, the plan for her life, has an item that she has never been able to check off; and the time has come to fix that. How hard can it be? All she needs to do is go on a date and get a kiss.

Now available in hard or soft cover!

Princess Celestia tires of constantly being surrounded by decorum, deference, and formality, and decides to take a day off from being Princess. But visiting Ponyville incognito is harder than she expects. Will she be able to fit in and make friends without blowing her cover?

"My name is Lyra Heartstrings, and you will not remember me. You won't even remember this conversation. Just like with everypony else I've ever met, everything I do or say will be forgotten. Every letter I've written will appear blank; every piece of evidence I've left behind will end up missing. I'm stuck here in Ponyville because of the same curse that has made me so forgettable. Still, that doesn't stop me from doing the one thing that I love: making music. If my melodies find their way into your heart, then there is still hope for me. If I can't prove that I exist, I can at least prove that my love for each and every one of you exists. Please, listen to my story, my symphony, for it is me."

Cover pic by Spotlight: askspotlight.tumblr.com

Twilight becomes alicorn of the stars. This is sort of a problem, because Luna kind of already was alicorn of the stars. Oops!

TV Tropes

Luna has had enough of Celestia's games, and has found the perfect means of revenge. Using a long-forbidden spell, she transforms her sister into little more than a small filly, all so she could pull the greatest prank ever. Unfortunately, she soon learns that before you fool around with dangerous magic, you really need to read the fine print...

A sequel can be found here.

When a freak reading accident causes Twilight to be admitted to the Ponyville hospital, Rainbow Dash is right by her side. Compelled by a sense of duty and repayment, she takes it upon herself to cheer up her friend.

Twilight is invited to Canterlot to compete with some of the greatest magicians in the world for the Moonstone Cup, a prestigious award for the most powerful and skillful magicians, unicorn and otherwise. Can she win? What sort of competition will she face?

Awesome cover image was taken from NoOneBahtim