I took him to lunch as the interview, part 1.
I then was able to question and test him on his knowledge, Part 2. (you know how fun that would be when I am asking the questions I already know the 16 possible answers too)
Part 3, allowed me to see how quickly he learned, if at all.
One note about Part 3, it was the really important part to me. If he can't learn, *I* don't want him.