Just because you're not Batman doesn't mean you can't use a hidden room that's camouflaged as a bookshelf. Maybe you have a collection that's worth a lot of money, or a super-secret lab—or, like YouTube user korostelevm, maybe you just want a good hiding place for your guns.
He turned his closet into a secret room hidden by a bookcase, complete with the obligatory movie-inspired book-for-a-handle trick.
To support all the weight of the bookcase, he used four heavy-duty casters, cutting off the wheels and welding on conduit box pieces in their place. These are mounted at the top and bottom of the door
Once he built the bookcase and placed it between the hinges, he added locks and the pulleys that open the door when the book handle is pulled. The cord is connected to the handle through a small hole he drilled, and the lever is hidden inside a space he cut out inside an old copy of The Grapes of Wrath.
After a few coats of paint and some new trim, you'd never know there's anything behind it. Plus, like korostelevm says, it actually makes the room look better, too.
Check out the video above to see a demo, and the Imgur album for more photos and details on the build.