BoxMaker is a little Java application that can generate the outlines for a box to be out of some material with a cutting device (ideally using wood/acrylic on a lasercutter!). You tell it the dimensions of the box (width, height, depth, material width), and it generates a PDF with the outlines for the 6 sides of the box. The dimensions are the outside lengths of the box. Here's an example of the type of PDF file it outputs.
Windows users, you'll want to double-click the "BoxMaker.bat" file. If a window appears and then vanishes, you might need to download and install the latest version of Java. The edges are notched, so the faces of the box snaps together well. You can import the PDF file that BoxMaker creates into CorelDraw (or any other standard CAD program) and manipulate it further there. You probably want to rearrange the faces to fit on the material you have at hand.
A new checkbox to output the PDF with a bounding box and the size of it. This can help if you are importing into AutoCAD, which never respect the original size of the box!