One of the PCs in my DFRPG campaign is basically a magic item thief, and I've been working on some wondrous items for him to encounter. I've got a good idea for a Magick 8-Ball that knows the answer to anything for a Fate Point, but gradually compels you more and more to forget things. When you get rid of the 8-Ball, the curse remains, eventually leaving you with the sole knowledge that getting the 8-Ball back can give you your answers again.
Anyways, it's a nasty item with what I hope is a tempting power. I have decided that to destroy the 8-Ball, you have to ask it the one question it cannot answer. The problem is, I have no idea what would be a good question.
I think that the 8-Ball will know the answers to "What is the capital of Assyria?", "What goes black, white, black, white, black, white?", "What is your favorite color?", and quite possibly "What is the airspeed velocity of an unladen swallow?". I would give a FP to the first player who tried hitting the 8-Ball with Monty Python by way of apology, but I'm not sure that should work on the artifact.
Any thoughts as to what would make a good question?