In the magical land of Equestria, two alicorn sisters raise the Sun and the Moon every day to give the world a night and day cycle, basic for the survival of life. There are also two alicorns who rule over two very core aspects of life and harmony itself. Those are Love and Friendship. While not as ancient as the two sisters, all princesses are essential to the world's balance.
This balance is also sustained by the hard-working ponies, who make the seasons change and manage the weather to fit their needs, so everypony has enough food and water, and every animal is also attended to assure that any of them are caught in the changes of seasons.

But what about the planet itself? What about Mother Nature?
This is the question that Gaia asks when she arrives to this foreign world. After so much work her son persuaded her to take a long vacation in Equestria, saying that she needed one and assuring her that he would be in charge now, and she must take a break. But what can a several billion-year old alicorn possibly do to pass her time in this land?

(SimEarth/MLP Crossover)
(Timelife of Gaia's life 'till the start of the story)

Years ago, Twilight preformed a spell to teleport a notebook to herself that she needed but had left behind at her home. The spell worked, just not as she intended. The notebook was actually a diary, and it was not hers. It was the diary of a human boy, she read the diary making foot notes as she went along until, much to her surprise, it vanished. The next day she tried it again to find that her foot notes had been responded too. Over the years the two wrote back and forth like pen palls. Their friendship grew and grew until one day the letters stopped, until today, today she receives one last letter.

The Princesses find an alien creature barely clinging to life at the scene of a terrifying crash. Can the Combined Power of the Elements of Harmony save it, or more importantly, should they save it? Will the arrival of this strange creature tear Equestria apart?

TV Tropes
https://tvtropes.org/pmwiki/pmwiki.php/FanFic/Article2

Reader, in ancient days, the old lords of the world numbered in thousands. Then hundreds. Then even less.
Now, they are found only in tapestries and fanciful ballads.
The creatures are all vanished. All but one.

Rumors say there are more of him, somewhere far away. A young and supposedly gifted mage called Star Swirl, and Heartstrings, a gentle spinster, have joined him on a journey to find the rest.

Featured in The Royal Guard's Fic Spotlight #5
TV Tropes page (that could use more love)

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?

It's the year 2559. The UNSC barely managed to fight off the hordes of the Covenant. That victory came at a hefty price. With the war over and the rebuilding process beginning, the UNSC Tuscany is sent out to investigate potential new worlds to colonize. It's crew and captain are in for a surprise when a gravitational anomaly turns into a tense situation where cooler heads must prevail.

Super-Edited Version Coming Soon

Proofread by: Alex Nuage and way2dawn

Now 100% Twilight's Library Approved
[img]http://i.imgur.com/6MrWqNZ.png[/img]

Awesome fan-art by Gothshy [Check it out]

In a world ravaged by the living dead, one man has outlasted those with far more strength, speed, and experience. His only advantages are his uncanny luck and peculiar inspiration. This inspiration has never led him astray and even promises a fresh start. All he has to do is build a strange device that follows no earthly science.

While Earth’s story might be over, this cog-jockey’s has just begun.

The star system Omega Centauri was just another oddity on a map to scientists in the not too distant future. However when they found the star was orbiting an earth-sized, earth-like planet instead of a black hole as its motion had suggested, a mission was scrambled to investigate this most unusual of celestial behaviors.

Hamstrung by politics, and nearly crippled before it began, the 'Lone Ranger' mission was reduced to just one crew member and left to his own devices.

These are the logs of Arrow 18 and its lone commander. This information is classified TOP SECRET by the Global Space Agency.

Do NOT tell the princess.