first of all, it depends on what the job entails. but some generic questions you can ask are
1) what was your biggest challenge in school/last job?
2) describe a group project
3) describe a situation where you had a disagreement with someone
4) where do you see yourself 2/5/10 yrs down the line?
5) tell me about yourself
6) why do you want to work for us?
7) why should we hire you?
8) why did you choose your college/major/last job?
and so on....
you can also ask microsoft-type questions if this is a technical job....
you need to get some discussion going. that's the best way to make the interviewee feel comfortable + get the most info for assessing whether the fit is right for your compay.
