The Keepers of Discord by Hoopy McGee takes place just after the events of "The Return of Harmony".  Discord has been imprisoned in stone once again, but unbeknownst to anyone else, he is fully aware of his surroundings despite being completely unable to do anything.

Check out the story on FimFiction.net:
http://www.fimfiction.net/story/25125/the-keepers-of-discord

Crazed Rambling Dramatic Reading:
https://www.youtube.com/watch?v=4HHzpTUU5fM

DRWolf Images by CiderSplice:
http://www.deviantart.com/art/DRWolf-Avatar-Confused-395260247

My Little Pony Characters and Images belong to Hasbro.