My family's idea of a physical activity is discussing where to go for lunch. Actually, my daughters discuss; my husband pouts if he can't muster a majority for cheesesteak sandwiches. Perhaps I would find this behavior charming if the Surgeon General were not running around the country complaining that we are raising the most sedentary generation of children in American history, if 1 in 4 kids were not overweight or if I liked cheesesteak.
But when I suggested that a sunny day seemed better suited to biking than to ingesting fried onions, my family reacted badly. "We already exercised," my 11-year-old...