At least I assume it's that one. It might be a completely different one. But who cares? It's an Avengers: Age of Ultron trailer. (I expect in the UK it'll have to be called Avengers Assemble: Age of Ultron... *g*)
I'll be in my happy Natasha Romanoff place. Squeeing and flailing like mad.
ETA: And now Marvel's uploaded it to Youtube, with embeddable links and everything...