For utility closet door. have cabnet doors on front to use as a pantry Love this idea for the basement, book shelf/hidden door for extra storage for kids stuff. Basement Basement Storage Design, Pictures, Remodel, Decor and Ideas - page 16
The inverted bookshelf turns your living room upside down as it hangs all of the books from the bottom instead of supporting them from below. It's a satisfying optical trick and doesn't damage any of the books.