I like free, easy, earth friendly, and practical projects. So this instructable is in that vein.
Make shelves and storage options with free existing cardboard boxes. You can turn it up a notch by painting or using contact paper to decorate the boxes if you choose to spend the extra time & resources, but for me simple works just fine. Also, sometimes the graphic on the boxes can actually be quite cool by itself.

This project makes going green easy. The material is readily available (for free), the equipment is basic if any, and the labor is minimal. The finished product is durable and still recyclable; my projects shown here have lasted more than a year with moderate use, and if I ever move, I'll just recycle the boxes and save on moving expenses and gas for the moving truck (reducing my carbon footprint).

Going green is very simple with a little imagination!

Step 1: Gather Supplies

Collect the appropriate boxes. A good source for boxes is your local BJs/Sams/Costco warehouse clubs. For this project I chose grape boxes, but you can pick any type of box to use as long as they are sturdy enough for what you plan to put in them. What is important is that the boxes are all the same so they can fit/stack together well.
Get out your handsaw or hacksaw, or anything that will allow you to cut through cardboard cleanly.

Step 2: Cut

Mark the middle of each box and take a handsaw and cut each box into half.

Step 3: Complete

Stack the cut halves and voila you have a shelf. Store your papers or shoes! In this picture I stack the half of the top box upside down to put my scanner on and use the rest to store my papers.