bookshelfporn: DIY Ladder Bookshelves To get this look, all you need are two ladders and some wood planks. Paint the ladders and the wood if you want, then slide the wood planks through the ladders so they are resting on the ladder steps.
Place painted foam board in the back of the bookcase, giving the look of a painted bookshelf w/out the commitment. Love this idea for a small book shelf next to couch. Good way to use yellow without committing to it in a big space.
Box shelves are inexpensive, easy to make and highly versatile. Make the combination of sizes and depths you need for any room, from the living room to the laundry. Box construction techniques are always the same.