The original Fantasyland "dark ride" attractions were of the "swinging door" design when it came to show elements. There is no better example than the classic Mr. Toad's Wild Ride, where plywood cut-outs would swing out of the way of the ride vehicle when triggered by track switches. While this type of ride design is still fun, it has become very dated.
Fast forward to 2009, when the Imagineers receive a patent for a ride system that uses magnetic levitation and superconductors (along with show elements on their own track system) that takes the "swinging door" design to an unbelievable level.
Check out these drawings from the patent application. Could a rebirth (at WDW) or re-imagining (at DLR) of Mr. Toad's Wild Ride be in the future?