Just moments ago, it was revealed that Warner Bros. is about to officially announce a Batman and Superman team-up in Man of Steel 2 for release in 2015. Following this news, they will also announce Justice League for 2016 and a Flash standalone movie for 2017.
While producer/writer Christopher Nolan, director Zack Snyder and star Henry Cavill will all be back for Man of Steel 2, it is not know at this time who will be taking on the challenges posed by Justice League and Flash. It is possible that Man of Steel 2 writer David S. Goyer will be involved in some capacity.
The biggest surprise of the day will be if they announce Christian Bale coming back as Batman. This is unlikely, as the actor claims he is done with the character. But that would be in-line with holding the element of surprise. Anything is possible.
You still have time to get to Hall H to hear the big announcements.