You can't have Super Bowl commercials without including a few trailers for the biggest, loudest, explosionest movies of the upcoming year. Pretty sure The Avengers qualifies in all three of those categories.
Also pretty sure Marvel and Paramount have enough money to buy all the Super Bowl commercial airtime, so it's a bit of a letdown to see they're only going with a ten second blink-and-you'll-miss-them preview of their superhero tentpole film.
UPDATE: Here is the full trailer.
All your old pals are back. Iron Man, Captain America, Thor, Black Widow and The Hulk. Sadly, Jeremy Renner's Hawkeye gets the shaft with no screentime. Then again, considering he's the Aquaman/Chris Bosh of this group, it's not all that surprising.
Marvel and Paramount are clearly saving the good stuff for a theatrical trailer release. And by good stuff I mean Robert Downey, Jr. quips, mean Thor glances and as many shots of Scarlett Johansson as they can possibly fit in a trailer.