Here is a movie I took of a ladybug larva (I think) eating another bug. I used the 5D II and a canon 100mm f/2.8 macro lens. It isn't the greatest, but it sort of demonstrates the potential of macro movies with the 5DII.
http://www.youtube.com/watch?v=s0P1sht887c
Be sure to watch in HD... better yet, in HD and full screen.
Has anyone else taken macro movies with the 5D II?