Just last night, we were saying that next week we'd see the official Avengers: Age of Ultron trailer following Agents of S.H.I.E.L.D. as announced by Marvel, and as if my magic the trailer has appeared leaked on the internet (no, Bleeding Cool had nothing to do with this). And we may have had nothing to do with this, but we wouldn't want you to miss out since it's definitely doing the rounds. Movieweb.com, by the way, has noted that since the trailer cited an April rather than May release for the film, this must be the international version of the trailer.
If the original has stopped working, here is another.