Here's what you'll need:
old steak knife or cutting tool
half a yard of fabric total in different patterns as desired
plastic sandwich baggies
sewing machine/needle and thread
Start with a cardboard box in the size you wish your bean bag toss game to be. Trim off all the flaps so you're left with a solid base to cut on. Draw your design on the box, including holes for the kids to toss bean bags through. I made the word "LOVE" with the "O" being a toss hole, and a couple hearts for Valentine's Day. Now carefully cut out your design using your steak knife or other cutting tool. A simple steak knife works so well for me and I have so much control when cutting out shapes like hearts!
Now you're ready to decorate your box. I painted mine with Crayola washable paints, which dry really quickly. You can also use construction paper or markers if you're in a time crunch. But really, the paint goes on fast and dries so quickly!
As that dries, start making your bean bags. Cut your fabric into 5 inch squares - you'll need two squares for each bean bag. I made a total of six bean bags in three different patterns. I found really cute, inexpensive fabric at Wal-mart for this project.
For the inside of our beanbags, I bought a bag of dry beans from the grocery store. Molly helped me fill six sandwich bags with about 3/4 cup of the beans in each and seal them up. Fold each bag in half, then in half again so it's the right size.
Place two squares together, with the fabric design facing each other. Sew around three complete edges, and part of another edge. Leave that hole open so you can turn it right-side-out. Then put the plastic baggie filled with beans inside your semi-sewn bean bag.