So I am writing a dark MLP fanfic... Not the best out there, you can be sure about that. But I thought some people might enjoy reading it anyways. ^^
Here is it's short description:
It starts as an ordinary, warm morning in Ponyville. But soon after all the little ponies get up from their beds something terrible happens: The sun suddenly vanishes from the sky. There are not even the stars or the moon to give light, darkness is a perfect blanket above all Equestria. Our little heroes decide to visit Zecora in hope of getting an explanation for what is happening. But not even the wise zebra knows what brought darkness. And just then, they realize they lost Pinkie.
Aaand, here's a link to the story itself:
Laughter Lost in the Dark