I'm so shocked that anyone else knows about this!! My sister and I did the trivia challenge close to ten years ago. We had a treasure map to follow at the time - not sure if this is the same thing you're talking about, but I do remember the trivia and prizes. If I recall, it wasn't something widely publicized, but we were in the right place at the right time. It remains one of my very favorite Disney memories of special things we did.
Unfortunately, I haven't seen or heard about it since that one and only time. Sorry...