Functional Ethereal Compass

By "functional" I don't mean you can actually navigate between dimensional realms with it, but "Nathanel's Fob" from artist James Ewing will do just about everything else.  It unfolds from a decorative watch fob into a fiendishly clever navigational device with all sorts of interactive fiddly bits.  This is easily one of the most creative and well engineered original props I've ever seen.