Here's a do-it-yourself project, complete with template. Note the template came from someone named Daren at peaceofpaper, but his Web site no longer exists (the new peaceofpaper is some sort of religious fanatic). He was giving this pattern away for free a few years ago, so I'm passing the template along here. His sample involved a lovely little gift box. I've converted that idea into an even lovelier recycling project using cereal boxes.
Just lift the image below off of this blog and onto your desktop and use it as a template (Important! Click on the image first, to view it at its full size, then lift that image onto your desktop. If you try lifting the smaller image below, you'll end up with a template that is too small. The image should be 7x9.806).
With the pictures above, you should be able to use your native common sense to figure out how it goes together. Note - you will need to print onto a legal-size (14 x 8.5) piece of cardstock - or print onto normal paper in two sections and glue to the back of the cardboard you're using. Enjoy!
And a postscript for lovers of nifty little boxes: follow this link - A Greener-than-Thou Advent Calendar - to a more recent post regarding how to make amazing little boxes out of recycled cardboard toilet paper tubes