Overview: "Dark Horse" profiles horse trainer Doug O'Neill who is attempting a comeback after being accused of 'milkshaking' his horses. "Anatomy of a Nasty Pitch" interviews pitcher R.A. Dickey and examines the physics of his famous knuckleball. "Darts Wonderland" takes an in depth look at the world of professional darts. "America's Cup" previews a story on the famous yacht race.