Is there a simple way to track the motions of a single entity in a webcam feed? For example, I imagine a "hello world" app with an index finger used as mouse pointer.
I realize there's still a lot of basic research in this area, so it might be too early to expect an easy to use, generic abstraction.
For the sake of completeness, I've seen some related but lower-level (and non-Python) projects being mentioned, including AForge, WiimoteLib and an article on motion detection algorithms.