Jeanette Mulvey has some great questions you can ask your potential employee during their interview. This is a fun read. Here are a few on my favorites:
What's your favorite restaurant? - The main goal of this question is to see if the applicant gets excited. I mean, who doesn't love to eat. If they can't rattle off at least one restaurant or let you know what they're favorite meal, is you may wonder what exactly gets them talking.
What would you look for in an employee if you were hiring? - This can tell you a lot about the person you're interviewing. If they tell you they're looking for some new best buddy's to hang out with, you may want to think twice.
What do you want to know about us? - If they don't have a few questions about your company they definitely aren't that interested or prepared.