Working with data from the CDC, MSN has produced this grim animated map of the rise of obesity in America from 1985 to 2004.
(Thanks, Fipi Lele!)
Update: Paul sez, "The CDC changed the definition of 'overweight' and 'obese" in 1998, making millions of Americans 'fatter' overnight."
Update 2: Steve sez, "According to the CDC's data _ALL_ the years are compared against a standard BMI measurement, BMI > 30, regardless of year."
Update 3: Jim sez, "One interesting feature of the CDC obesity data is that it's based on people's self-reported height and weight collected through telephone surveys, rather than being based on actual measurements of patients reported by doctors and physicians."