Two: 48"x 24" sheets of 1/2" plywood
Three: Eight-foot 2 x 4s
One: Box of deck screws.
One: Can of high-gloss primer paint
You'll want to follow exact instructions, many of which are available on the Internet along with construction diagrams. However, here is a quick overview of what's entailed to give you a sense of the project:
Cut the 2x4s in four equal four-foot sections.
Affix the 2x4s to the underside of the decking along the sides. Cut the remainder of the 2x4s into roughly 21" sections and affix them to the front and back of the boards between the side rails.
Make a mark on the boards exactly nine inches from the edge of the board in the center of the platform. (12 inches from each side.) This is the center of the hole.
Take a compass and trace a perfect circle on a three-inch radius from the center mark. The finished circle will measure six inches in diameter. After drilling a starter hole, take a jigsaw and cut out the cornhole. Use sandpaper to smooth any imperfections.
This is a matter of personal preference. Some people prefer to use leftover plywood to form a 12-inch stand that can be affixed to the bottom of the boards with hinges. A more effective approach is to use 12" sections of 2x4s and affix them to the sideboards using bolts and washers. The bolts can be removed and the legs folded under the boards for easy transport.
You're almost done, so don't screw up your boards. Sand the surface of the boards using a low-grit sandpaper. Then paint the boards in the NFL or college colors of your choice and affix team decals.
If you've got someone in your life you who loves crafting, this may be a job for him or her. You'll need some fabric and dried corn kernels (hence) the name. Bags should be double stitched and weigh approx 15 oz. Or go to the American Cornhole Organization's website and order pre-made bags for $20, or NFL bags for $25. Skol Vikings!