The next bit of Fallout: New Vegas DLC, which will be called Old World Blues, will be available on July 19th. That's the first image of it up there. What we know at present is that the plot is based on your being a "lab rat" in one of the experiments that produced many of the mutants that inhabit the game, and you will be able to either fight your kidnappers, or join with them to take on a "larger threat". It will also raise the level cap and give you some other options, such as talking to robot appliances.
Bethesda have also sent word that a significant update for the game will appear before this DLC, providing "improvements to performance and stability in major areas".
Major areas. I don't know that that means, but it sounded significant enough for me to want to emphasize it in a military briefing sort of way.