With a wood slab—try one that's at least a foot wide—and a few strips of yarn or leather, you can create this portable tic-tac-toe game. (Consider keeping it in the car!)

Start with the wood slab, then format the strips into a grid as shown. Use upholstery tacks to secure the grid in place. For game pieces, you can use pinecones, rocks, acorns, seashells, leaves, or daisy or dandelion heads.