What sorts of activities have you gotten involved in / are you interested in joining? Do you do any sports? Do you play an instrument? etc. (You may have something in common. It is a bit overused, though.)
What TV programs do you watch? -or- Do you watch <insert name of popular TV program>? (could backfire if they don't)
What do you like to do with your free time? (Then follow up on it. For instance, if the PNM is an avid cross stitcher, ask her about her current projects.)
Here's one to avoid: So, do you have any questions about XYZ? When I went through FR, there was one sorority where I think every single sister I met asked me that. I had a few prepared questions, but I ran through them so fast that I ran out of questions! PNMs are nervous enough as it is