I believe Aerys (the mad king) had an affair with Joanna and is in fact the true father of Jamie and Cersei, ironically leaving Tyrion as Tywins only true child. Evidence for this is that targaryen's were incestuous (as are Jamie and Cersei) and throughout A feast for crows you can clearly see Cersei becoming more and more crazy...she's definitely Aery's son in that regard. So yeah I think this is pretty plausible. Another theory I've had us that Arya will kill either Jamie or Tyrion(most likely Jamie as GRRM loves Tyrion too much to kill him off I think) and steal their face(once her faceless training is complete ofc) and subsequently be the Valonqar that kills Cersei. Also Cersei is on her list of people she says she'll kill so...
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right
