This isn’t official, so I’ll just leave this link quietly over here.
Highlights: ammunition for COULSON / ROGERS shippers, Maria Hill freak out, Thor The Juggler, and Joss Whedon breaking up arguments like a 5 year old.
This gag reel will most likely be released on the AVENGERS Blu-Ray, due September 2012.
Update: the YouTube link predictably got taken down. So replaced it with the one on io9 :)
Update II: And the video keeps dropping off the face of the Internet. io9 was requested to remove the video. Sad Hulk face.