I just got my 5d Mark II and took it out to the Vancouver Aquarium for it's first outing. Here are a few initial test clips, shot with the EF 50mm 1.4 lens. I have much to learn about the camera and it's video functionality.
In addition to aquatic life they also have several monkeys along with a very dark bat enclosure. I was surprised to see that the bats actually turned out fairly decent considering the extremely low light levels.