Whateley Academy Fanfiction
See http://www.crystalhall.org/whateleyfaq.html for the FAQ, http://www.crystalhall.org/index.html for the main site, http://www.crystalhall.org/stories.html for the stories, and http://www.crystalhall.org/chboards3/ for the forum.
Go there to find stories. Stories about teen aged kids who happen to be mutants. Their powers will lead them to eventually become super heroes, super villains, or perhaps something more complex.
With "This is fan fiction for the Whateley Academy series. It may or may not match the timeline, characters, and continuity, but since it's fan fiction, who cares?" on the front, you can write whatever you want, and post away.