I would like a perfect sphere you could walk in that was a flawless mirror inside, like a house sized fishbowl. Get Some large beach-ball sized glowing marbles (Suns) and some large gorilla-fist sized planet marbles (perceived[e.g. Niflheim] and known[e.g. Earth]) and some smaller mirror-marbles to create a kinda of infinity.
Oh and zero gravity and the marbles could bounce and the mirror-sphere could flex. It would be good if the planet marbles were edible and tasted like a hybrid of various fruits, suns taste like sugar.