Cersei Comes Clean
It seems like the whole world knows it, and Tywin himself probably already knew it, but Cersei decides to rid herself of the burden of her great and terrible incest secret to her own father. I mean, she has a point; how could he not have seen this happening under his nose? It seems like she's doing it so she can be with Jaime — she tells Jaime she chooses him just after her confession. It'd be so romantic, if you know, Jaime WERE NOT HER BROTHER.