User blog comment:Tdiandrockmusic2/I have an idea.../@comment-1324135-20100208223757

Oh, I remember those! Those are usually posted on places like LiveJournal. I think there are entire communities dedicating to posting fanfiction/icon/fanart challenges (some of them being fandom specific, some not). The person will post a challenge such as "write a oneshot about your least favorite pairing" or something like that and people will respond to them on their own journals/accounts/whatever. I've never responded to a prompt before, though.

This sounds pretty cool, though!