Needed to make a new hatbox. It'sa simple project of cardboard, so here goes!

Step 1: Lay It Out

To lay out the oval, you will need a trammel bar and a square. I had a framing square on hand, and made the trammel out of (Guess what) cardboard.
lay down two perpendicular lines in a cross. Now place your square against two lines and hold or clamp in place.
For the trammel bar I bent up the end of a strip of cardboard and taped on a fine point sharpie. then I punched holes and inserted sharp pencils for the points
For the points you need to measure from the marker point to the pencil hole 1/2 the major axis and again for the other hole 1/2 the minor axis. In this case I wanted to overall to be 12" x14". so the pin holes were 6" and 7" from the marker tip. that's pretty close together to and makes it a bit tricky to operate, but You can do it.
now poke your pencils or whatever you are using for points through the holes and run them along the legs of the square. start with one point at the corner and draw it down the vertical leg while the other is run across the horizontal leg of the square. If bothpoints are kept tight to the square, the marker will have traced out one quarter of an elipse.
Now just flip the square to each remaining quadrant and lay out that section of the oval.

Step 2: Cut It Out!

Make sure your hat fits nicely inside the oval with plenty of room to get it out of the box. Now just cut out the oval very neatly. measure around it with a flexible tape measure to determine how long the side piece needs to be. add one inch to this measurement for overlap. My box needed to be six inches high, so that's how wide I cut the edge piece. You want the ribs in the corrugated perpendicular to the long dimention of the edge strip.

Step 3: Put It Together

Now take your edge strip and break it over your knee or the arm of a sofa etc. so it will curl smoothly.
wrap it tightly around the oval and mark the overlap. You want it to be nice and snug.
Glue and staple the overlap together.
once the glue has dried a bit, press that ring down on a hard surface and push the oval piece into it until it is flush with the bottom of the ring. Use some tape to hold the side and bottom together. start by putting a piece of tape about 4 places around the edge and then fill in completely. Pull each piece of tape up tight and smooth it down nice and flat.
Now turn the box right side up again and run a bead of glue all around the junction on the inside. When the glue is dried, the box part is done.

Step 4: The Lid

Now for the lid, It is made in exactly the same way, but it is of course a fraction larger so it will fit over the box. the edge band is only about one and a half iches wide.
To lay out the lid, put the completed box on another piece of cardboard and mark around it.
Hold the pencil flat against the side of the box so that the lead actually marks about 1/8" outside of the box. now duplicate the instruction for the box to make the lid.

Step 5: Decorate

I haven't decorated my box yet, but I was thinking of decopage with old timey black and white graphics etc. You could glue on wallpaper, or cover the whole thing with paper mache' if you wanted, or glue on foam cutouts, ribbons or whatever suits your fancy.
I've given you the structural part, you supply the creative juice.