The Marvel team is apparently releasing two different posters daily until all the major characters are completed. Each poster is done by a different artist and is being given away at the Marvel booth (#2329) on the said event until supplies last. So far only four have been released... keep on coming back for the rest.
Check out these fantastic concept art posters of Avengers: Age Of Ultron.
Hint: These posters are actually puzzle pieces to a bigger picture.
The Avengers must assemble to combat the threat of Ultron!
As the US Government create a force, known as Ultron, The Avengers are told they are not needed any longer. But when Ultron turns against Humanity, it's time for The Avengers to assemble yet again for their most dangerous challenge ever.
Marvel's Avengers: Age Of Ultron will reunite the greatest superheroes once more. In theaters May 01, 2015.