Fantendo
Fantendo is an enigma of a wiki/site/database. Its original purpose was for Nintendo games and Fanfic. But it slowly changed into a database for stories altogether. You can create original, crossover, whatever types of works on it. Fantendo has quite a few nice ones, though almost everything else sucks.
Had an Alternate Reality Game contest that flopped.
Feel free to visit Fantendo and make pages about the various works there.
Works on Fantendo include: