Lately I've been reading lots of Harry Potter. Anyway, I was stumbling around the internet and read a few most interesting theories.
That Ron goes back in time and becomes Dumbledore and that is how Dumbledore always knows everything.
About that whole chess game being symbolic (from SS). Hmmm... very interesting.
http://www.knight2king.net/Knight2King/Personal56.html << Explore that.
EDIT: and by interesting I actually mean that in an entirely plausible way... i'm not slamming it. it's very thought out.