Like shipping pallets, wooden cable spools are another item that is usually found for free on Craigslist. Since cable spools are limited by their shape there are fewer repurposing options, but they make a great coffee table bookcase.
Cage Free Sustainability: Don't be afraid to reuse in your design. We can't take our eyes off of this idea combining two of our favorite things: books and lighting. (recycled lamp DIY : Books table lamp in paper lights diy with Light Lamp DIY Book)