RPGs involve a large number of people who take turns to write the story as they go, more or less. Fanfics are usually written by the one person, and aren't a group-based activity. (Unless they're co-written but in that case the writers fully plan it out and know/agreed on what is written, where in RPG's it's a looser 'anything goes' format, within some sort of limits [usually the 'don't break the rules/derail the story stupidly type =P]
As for stuff I've done...well, check my signature - the banners there are clickable and should link you to the stuff I've done and put up here. =) Enjoy. And now I sleep.