I know the thread is well past this by now, but I just had to comment, for people who haven't interviewed yet... If you're feeling *really* cocky and you get somebody like this, you could call him on it. We've got this "doctoring" class which is mostly about communication skills in the freshman year, and they get really insistent on good nonverbal communication - to the point of one of the profs telling us how offensive it is to fall asleep or read our e-mail in class and that he'd rather we leave than not pay full attention. (As a one-time teacher I tend to agree, but the fact that they emphasize it so much makes it all the funnier that they've got Dr. Bored interviewing you.)
So you could just pipe up with "I'm sorry, but I'm just noticing that you're exhibiting some really negative nonverbal communication... are you all right, or is something distracting you?"
Of course it would really only be funny if they get that you're making a reference to the class.