Mental Floss (known for giving us "Random, Interesting, Amazing Facts") has put together a great quiz: Nancy Drew or the Hardy Boys. They give you a title that comes from one of these two series, and you have to decide (guess? remember?) which series it is. No cheating, of course, but if you get inspired to read or re-read any of them check out the many, many Nancy Drew and Hardy Boys mysteries at your library.
P.S. I failed! There were only two that I actually knew, but I got 8/15 right. How about you?