Don't make the questions too difficult though like pizza hut did if you forgot your password.
They had a question like this once:
How can a photon of light be in 2 places at once?
Now i know it has something to do with quantum mechanics/physics, but I just wanted some freaking pizza, not spend 30mins trying to find an answer that will fit in the word limit, LOL.
But yea, a simple yes/no questions should work. I dislike capchas too, sometimes there just to hard to read.