So the February 1 issue of "Entertainment Design" magazine has a loooooong article detailing all the ins and outs of making the magic happen on the Gershwin stage.
This is pretty in-depth stuff: The Clock of the Time Dragon is mounted on a wagon and stands as high as a giraffe. It is nothing more than a tottering, freestanding theatre, punched on all four sides with alcoves and proscenium arches. On the flat roof is a clockwork dragon, an invention of green painted leather, silvery claws, and ruby jeweled eyes. Its skin is made of hundreds of overlapping discs of copper, bronze, and iron. Beneath the flexible folds of its scales is an armature controlled by clockwork. The Time Dragon circles on its pedestal, flexes its narrow leathery wings (they make a sound like a bellows), and belches out sulfurous balls of flaming orange stink.
If you want to get the inside story, here's the link!Broadray weblog