Turning the Tables
Actually, you can't turn the tables on your interviewer (he already has a job, after all), but you can take a look at his body language and evaluate how well the interview is going. Just be aware that the person who's conducting the interview might not care in the least whether you're hired or not. His job might be limited to conducting interviews and passing along your information to someone else who makes the hiring decisions. Why should you know this? Because if your interviewer's body language is saying to you “I hate you. Get out of my office,” you should still hang on to your professional image. It's not going to hurt you, and in the end, there's always the possibility that it'll help.
So what are some signs that the interview isn't going as well as you'd hoped? Generally, be alert to any body language that indicates boredom or hostility coming from your interviewer, such as:
Nonexistent eye contact
Arms crossed tightly over the chest
Head angled away from you
Keep in mind that body language is a study of patterns of behavior, another reason for you not to lose hope. For all you know, this guy always looks bored, or maybe he does this to test an interviewee's mettle. It's best for you to continue on with your plan (which, if you've forgotten, is to project an air of confidence) no matter what your interviewer's body language is saying.