Here's a project that I was involved in, in my personal time. It's Resort World Sentosa's publicity for their Halloween event.
I helped out in a single key shot shot where crows fly out of the mummy's mouth (in the end they I think they kind of looked like flesh coloured bats).
I matched the camera perspective and movement, then I matched the movement of the mummy's head and mouth. I also had to match the torch light for illumination and shadow casting. There actually is a handheld light torch light in the scene. My partner then refined a provided model of the crow, rigged and then animated them flying.
The original shot was much longer than the final one, and it looks like it was sped up. Therefore there was a lot of camera, face matching and torch matching work that went into it that did not show in the final shot. In many cases this is the nature of the job.
This is considered a nightmare in a matchmove artist's dreams. Firstly, there were no geometry describing the physical environment, so I had to build geometry from the plate. Secondly, there were no trackable features in the shot that were visible for any decent length of time to track with a camera-matching software. Therefore I had to resort to animating the transformation of the camera by hand. Lastly, there was no geometry for any part of the mummy, so I had to approximate the face and head-dress with a very rough geometry.
I will post some wireframes showing work in progress for this shot in the near future.