Three weeks into the college football season, a service academy finally will play a home game against a Football Bowl Subdivision opponent. Here’s what Army fans need to know: Who, where, when: Northern Illinois (1-1) at Army (0-1), Saturday, noon Eastern. Army fell 49-26 at NIU last year. TV: CBS Sports Network (Ben Holden and Randy Cross have the call). Gambling is illegal in most states: Northern Illinois is a three-point favorite. Headline only a Navy fan can appreciate: Courtesy of NIU Today. At least he’s gone: Last year, NIU quarterback Chandler Harnish accounted for six of NIU’s seven touchdowns…