This could be a fun way to create Calder acrobats! Swing From An Empty Shoe Box Project For Kids - by Krokotak - == - By Russian educative website Krokotak, here is a cool project for kids, with a tutorial full of photos that dispenses words.
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.