Rotoscoping is used to capture realistic human movement by drawing over film footage of live actors. Perhaps this sounds like cheating, but adding an artist's vision to the movements of a human actor can create a unique storytelling medium that is just as stylistic as any other form of animation.
One of the most sophisticated examples of rotoscoping is the film Waking Life, starring Ethan Hawke and Julia Delpy. Waking Life took the 2001 Sundance Film Festival by storm, impressing audiences and critics with not only its animation style, but director Richard Linklater's ability to tell a moving, rich story using a frenetic animation style like rotoscoping.
A much more simple example of rotoscoping is Tom Goes to the Mayor on Adult Swim. Actors are photographed performing the scenes. Then the photos are digitally processed using a graphics filter. When the rendered photos are strung together, the story is told using limited animation, no lip movements and little movement in arms and legs.