A small, AIR Client only patch has been deployed to the PBE!
Two new skins, Debonair Jayce ( file name Gentleman_Jayce ) and iBlitzcrank, have shown up in the client, although neither of them have models yet. I don't have any other information, but I feel iBlitzcrank is likely a celebration skin for the still in testing Mac client.
As for exciting changes, this is about it. Hopefully we'll see another patch later tonight with models or more changes.