I like the open-ended questions as well.  My last interview for my current employer was interesting.  He asked me 3 questions but I answered 10 questions.  He asked number 1, my answer and explanation answered 1,2,3,4.  He asked number 5, my answer and explanation covered 5,6,7.  He asked number 8, and yes my answer covered 8,9,10.  He was done in less than 15 minutes.  And the rest is history as I am still work here.