Scott Adams coins a new one:
Suppose we define a creature to have consciousness and free will if it demonstrates the ability to use the external world to reprogram its own brain toward specific ends. By this definition, reading a book in order to change one's mood or gain data would be an example of both consciousness and free will. But a monkey using a stick as a tool to get bugs would be nothing more than eating. The monkey is not trying to become a smarter or happier monkey; he's just feeding his body.