After Celestia and Luna decide to make a casual visit to Ponyville, Celestia is called away to deal with an infestation in Fillydelphia. This leaves Luna to find out about the mess Ponyville is after their own parasprite infestation. Will Twilight Sparkle be forgiven for her mistakes? Will Ponyville survive Luna’s prankish streak? Will Godzilla show up to fight the giant parasprite that’s appeared in the center of Fillydelphia?

This fic was featured on Equestria Daily on September 6, 2011, well before Luna Eclipsed aired.

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 Moonage Daydream, the loudest, most dazzling Pony Rock star in all Equestria, pays a visit to Ponyville, almost everyone is excited — except Twilight Sparkle, who just wants a quiet, dark place to do some stargazing. But when Princess Luna shows up and offers to help, will her solution be worse than the problem?

Yes. Yes, it will.

Now with a Spanish translation by Spaniard Kiwi!

After failing to stop Nightmare Moon in the ancient castle of the pony sisters, Twilight Sparkle is left with a scar that will permanently change the rest of her natural born life. As Twilight recovers from her ordeal, she finds that she is left with a difficult choice. Either live her life as a lie or sacrifice her innocence to protect the ones she loves. The path before her is set and she must now walk it alone. The sands of time continues ever onward, with everyone already trapped in its muddy depths. The sun will rise and the sun will fall. Waiting for its call, Death awaits for all.

Tags, rating, and characters can change.

Art created by:
http://cuteskitty.deviantart.com (top)
http://ventious.deviantart.com (bottom)

I just put the two together

Twilight Sparkle is, of course, a genius. Her insatiable love for books has made her a walking encyclopedia of all things magic. But you can't become truly great in academia just by reading books; Albert Einstein didn't invent the special theory of relativity by reading about it in high school. Well, Twilight has aspirations of true greatness. Her world is full of mysteries that she won't find the answers to in her library, and she's determined to be the one to solve them. And all the while, a villain wielding a brand of deadly, unknown magic is threatening both her friends and the whole of Equestria. What's a unicorn to do?

Being a genius isn't quite enough. Luckily, Twilight is also a scientist.

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This is an old story that takes place in the canon circa season two. It involves a slight re-imagining of Twilight to make her more of a scientist than a science fangirl. This doesn't mean she's no longer a cute nerd; if anything, she's more adorkable than ever.

A diplomatic crisis arises between Equestria and the small, poor kingdom of Tarandroland, ancestral home of the reindeer. Celestia and Luna agree that it is time Luna takes a more active hand in foreign relations again, and Luna brings Twilight with her as someone she actually trusts and can talk to. But the mission turns out to be much more than political discussions - if scheming unicorn courtiers, unfriendly surly reindeer, bloodthirsty pirates, ancient sorcery and dangerous monsters weren't enough, our heroines must deal with something old - older than Luna. And is Luna really ready for diplomatic action, will Twilight learn to use a fan properly, and exactly how wrong are Spike's superhero comics about reindeer mythology?

Now has a TV tropes page

Luna's isolation and difficult reentry into Equestrian life has left her without the confidence to communicate with the ponies around her. Especially the one pony she most wants to talk to. Celestia is angry, Twilight is upset and it's all her fault. Then she has an idea... She'll invite Twilight into her dreams. What could possibly go wrong?

A short story for Twilight and Rainbow Dash. Twilight invites Rainbow over for tea, and realises how much she enjoys her rainbow-maned friend's company. With some philosophy from Celestia and Luna.

Emotions really depend on double coincidence of wants.

It's Luna's first morning in Canterlot, and she's having trouble getting sleep. Maybe her sister has something to help...?

This was inspired by a picture by C4tspajamas, available here.