Step 1: Buy a medium sized square box, 4 different colors of orange, 2 browns and black craft paint. Get out a large ruler and a pencil. (I found the perfect size box at Walmart for less than a dollar.)
Step 2: Get over specific and search the internet for examples (none found? how is that possible?) and then move to pictures to be your guide. Find this one and print it out.
Step 4: Draw out grid and numbers onto your box. Make sure you mark one side for the face.
Step 5: Use an exacto knife to carve out a face on one side.
Step 6: Paint until all your dishes are dirty and no one has clean underwear.
Step 7: Glue the top and bottom of the box shut and then paint the top remembering that this grid should contain the stem in the middle.
Congratulations! You now have the coolest 8 bit cardboard pumpkin ever.
The good things about this project are no pumpkin guts, it won't rot, and I can save it for next year.
The bad things are that the painting gets tedious if you don't space it out and you can't put a real candle in it (that one isn't too bad because the fake pumpkin lights are pretty cheap)
Learn from my mistakes. Think about what side you put the face on before you carve it. Mine ended up on a side where you see the edges of the top. It would look better if I had done it on a side where the fold was. And yes, I could have just changed which flap folded to the top, but two of the box flaps were printed with a large black UPC which would have been hard to paint over.
Update: I realized after posting that I didn't have a picture of the top grid layout, which is very different from the sides. Here is the layout I used.
In case you can't figure out my complicated code, 1-4 are the oranges with 1 being the lightest. B = black DB = dark brown, and LB = heliotrope ... or maybe that was light brown, I forget.
UPDATE: Check out the one I did for 2014