Matt Damon to narrate Boston Marathon documentary

BOSTON - The producers of the first full-length documentary film about the Boston Marathon say they've signed Matt Damon to narrate it."Boston" premieres in its namesake city on April 15, two days before the 121st running of America's most venerable footrace. It will be screened in 500 theaters nationwide starting April 19.Executive producer Frank Marshall says the Academy Award-winning actor - who grew up in Boston and cheered on the runners as a young man - "is the ideal narrator."The film dir