Have any of you ever wrote a fan-fic about the boys?

No, but I found some good ones. And by 'good ones' I mean no yaoi included. It's freaky. By the way, I think 'BSB On Titanic' is pretty hilarious (though a little bit offensive), read it if you haven't yet.

I''ve got the impression that it's illegal to write fanfiction about real exsisting people? I mean that even the Fair Use statute of the copyright law does not cover the asses of those who do that.

As it's one thing to create a fictional character inspired by a person than to actually write fiction about a real person.

I know I wouldn't appreciate people writing fiction about me, no matter how respectful the content would be.

So, no. I have not written fanfiction about any really exsisting person.