What's the hubbub at Comic Con in San Diego this year? As usual, lots of blockbuster movies, lots of TV shows and lots of celebs, though none are likely to create that stir that a surprise, very brief, appearance by Johnny Depp caused today.

Depp, star of Tim Burton's March 2010 spin on Alice in Wonderland, showed up to give a quick wave to fans gathered to catch a first peek at the movie, and created such excitement that the "Decibel level (went) to 11," according to one fan on Twitter.

What's all the fuss about, aside from the general buzz a sighting of Depp in person can spark? The trailer for Alice: