Before hosting Discovery's "Dirty Jobs," Mike Rowe had a program in San Francisco about folks on a mission -- mad scientists, eccentric collectors, devoted do-gooders -- called "Somebody's Gotta Do It." Now, CNN gives Rowe free rein to scour the country for people who, he says, "do what they do because of a weird mix of love, compulsion, obsession, dedication -- whatever it is. Those people have always interested me." The former series focused on the task, but this version spotlights the personality. Or, as he puts it: "More mission, less poop."