That Boston will go purple on April 24 in support of ex-Celtics guard Chris Herren’s new Project Purple, a campaign that he hopes will change the bullying culture that kids who don’t use drugs or alcohol face in school. The Fall River homey, whose own substance abuse battles have been well chronicled, has enlisted the Pru — where the kick-off event will take place — to “light up” purple. Ditto for the State House, UMass Boston, the infamous “gas tanks” and State Street Bank. Also, the Celtics will honor Herren’s Project Purple during the Green’s game at the Garden against the Miami Heat. What a score!