In fact now that I think about it, it might be a good test to see if they are passionate enough to be a great problem solver:

When was the last time you wrote a sorting algorithm?

Acceptable answers:

- You mean sorting a list? - In school - Why would I write a sorting algorithm? - Never - (Glazing eyes and other body language that indicates frustration)

Red Flags:

- Anything that indicates they think writing a sorting algorithm is a perfectly logical thing to do during the course of software development.

(Note: The problem is sorting may seem like a well-understood problem, but it’s actually not. Only a person who studied the algorithms in school as an assignment would feel comfortable with that code.)