... is something I've never been all that interested in. I like world building and creative writing, yes, but I like to do it myself.
Or, at least, I hate to feel like I'm mucking up a different author's world by handling it poorly myself.
Still, I have tried my hand at it once or twice. It's somewhat simpler than creating my own stuff from scratch, since a lot of the setting is already built, and I have a list of characters I can try to use at need. That doesn't entirely excuse me from the need to build my own supporting characters and establish critical details of the setting for people who may not have read that part of the original source, but I would be doing that anyway if I created my own setting.
So the point of this post is in a link: namely, to my FanFiction.net profile. Not much there as of yet, but I'm going to try and get back into that pastime.
It'll probably drop off the radar again in a few months (rampant cynicism alert!) but I should be able to say that at least I tried.