Tell me about yourself.
Focus on relevant skills and experience. Be on guard against the interviewer who gives you free rein. Don't spend too much time answering (1-2 minutes). Avoid details. Don't ramble. Touch on four areas: Born and Raised, Education/Military Background, Work Experience, Current Situation.
[That's it. Now it goes without saying that how you sum your life should have something to do with why you're qualified to do the job they're interested interviewing you for.]