Besides the topics that eyepopslikeamosquito mentioned, the generic 'what was your most miserable failure?' with a followup of 'what would you have done differently, in hindsight?' can give you some insight into a person's personality.

From the last time I had to hire someone, here are the generic questions that I asked:

• Tell us about yourself (note -- forces them to summarize their resume to what they think is important)
• What is your most proud accomplishment, and why?
• What action do you most regret, and why?
• What is the worst job you've ever had?
• What goals do you have in your career?
• What are your long term goals?
• What motivates you?
• What is your greatest weakness?
• What specific skills and experience do you feel set you apart from others who might have applied for this job?
• Why do you want to work for (insert organization)?

update: fixed a typo.