This is a tamagotchi style game that combines text messaging with playing cards - kids have to make health decisions for their character to help them grown strong and healthy. Having a score so that kids can compete against each other might further encourage participation.
The children earn points throughout the game which result in food vouchers for their parents. The more the kids play and have fun, the more they learn lifelong lessons about nutrition, the more food vouchers their parents receive to buy healthy food.
This idea came out of the Manchester OpenIDEO meetup team.