Boston Running Company

When Diddy ran the New York City Marathon as a last-minute, made-for-MTV fundraiser/publicity stunt, he was able to enlist the legendary Alberto Salazar to help him through his crash-course, five-week training regimen. You, obviously, are not Diddy. But you can at least have your stride expertly analyzed by former Olympian Mike Roche, who will film you jogging on his in-store treadmill, study the footage in slow motion, and then put you in the sneakers best suited to the quirks of your stride. Just be sure to give yourself more than five weeks to train for your big race.