This is fantasitc, I suggest these questions should be asked when we need more PPC people. :-)

Some good common sense approaches here.  I like the situational questions a lot.  One of my favorite questions is to ask someone, "Tell me about a campaign that failed no matter what you hit it with."  By using statements that encourage them to continue speaking, you can find out their level of creativity, whether they blame others, and most importantly, what they learned from the experience.  I love that question.  Don't tell me what you do well. Tell me how you messed up.