Kellogg's World's Champions Cereal League

The Kellogg's World's Champions Cereal League was a game printed on the inside of a box of Kellogg's Corn Flakes. The box had to be taken apart and laid out flat in order to play. The panels on the box included the play area, a score card, and the game rules. This is considered by experts to be the first sports-related promotion in cereal-box history.