As much for my own reference later as anything:
You'll remember that I was on a PerplexCity kick a year ago or so. That was a collectible (sort of) card game, with each card having a puzzle on it, and an emergent puzzle as you got more and more cards. The cards were color-coded, from red to purple, plus black and silver above the normal progression through the spectrum.
So, I just had a dream featuring a purple card - not one that I had ever seen before, a new one emerging from my subconscious.
The card had a grid of squares with a jumbled up picture, which the solver would reassemble a little like a jigsaw puzzle into a picture of a patch of pumpkins. In each square, there was a picture of a jack-o-lantern and a word. The face of the jack-o-lantern could be scratched off to reveal a clue or instruction (e.g. "remove all pumpkins with three teeth"). By following the instructions correctly, the words would come together to form a riddle, which would then be solved to yield the answer to the puzzle.
It would be a bunch of work to solve, but I think it could be fun.