One of the best things we've seen at E3, hands-down, has been the cartoon introduction to The Beatles: Rock Band. It was directed by Pete Candeland, of Gorillaz and Guitar Hero II animation fame. Seriously, this thing just makes our jaws collectively drop every time we see it, and we wish this was what the game actually looked like.
The animation magazine Frames Per Second has the most accurate description of the trailer: "They manage to tell the career-spanning, mind-bending story of the Beatles in a couple of minutes, seamlessly blending well designed 2-D and 3-D styles of animation." We agree.