My suggestion: use a nonsense answer and use it for all of them. I don't reuse passwords but for exactly the reasons you state the answer to all my security challenges is something like "Because a kipper doesn't red the blue."

Alternately have a few nonsense phrases for stock challenge questions (first car, first pet, favorite <thing>, etc.) It's better than using the real (googleable) answer.

Finally, as Dale Carnegie would have loved: the more absurd it is the easier it is to remember. So while you won't remember if your favorite movie is the matrix or titanic, but you WOULD remember "I clocked blithely cookie everywhere." as the answer when you see that question.