Ohh you guys! Always keeping us on our toes Marvel Studios has scheduled two untitled movies for a Summer 2014 release. The first is scheduled for May 16th just two weeks after The Amazing Spider-Man 2 while the other is set for a June 27th release.
With all the recent rumors there are a number of titles that could fit here. Keep in mind the next few Marvel releases are:
The Avengers (May 4th, 2012)
Iron Man 3 (May 3rd, 2013
Thor 2 (July 26th, 2013)
My guess is Captain America 2 and I am going out on a ledge here and say a new Hulk movie. What do you think?