Since we are looking at facial CG animation - Image Metrics are doing astounding things!
From what I can see there isnt just a piece of software we can grab from them to do these amazing things, and they have hefty clients that are no doubt paying large dollars to get their tech and expertise. The fact that it is markerless is very cool, being able to grab performances from anywhere would be an exciting development...
CGSociety have a short article on their work, but perhaps we shall let youtube do what it does best:
For an example of a similar system using markers check out this vid of Pendulum's Alter Ego.