For the Castle room? we could build these out of kleenex and tp or pt rolls to decorate the tops of the shelves. We could also make this a kid competition, collaborating with math and art. Top 5 displayed in the Fair.
TOWERS/CASTLES (could be modified to all themes): Craft with shapes- Make a castle/tower/bridge. Can cut shapes from felt for the flannel board for repeated picture making, construction paper, foamies, etc.