This is a bit old, but still cool: the film Coraline (based on a great book by one of my favorite authors) was stop-motion, not CG. However, the facial animation was extremely smooth, due to a unique process. The expressions were modeled by computer, exactly as they would have been for a CG animated feature. Then for each frame, the faces were “printed” out on a “3D printer” (rapid prototyping machine). These tweened “frame faces” were swapped in for each stop-motion frame. CGSociety has an article describing the production pipeline for this film, an intriguing combination of CG and stop-motion animation.