Cambridge-bred actor Matt Damon took time out of his busy schedule — the Hollywood homeboy is currently filming a sci-fi flick, “Interstellar,” with director Christopher Nolan — to help education historian and activist Diane Ravitch promote her much-discussed new book, “Reign of Error: The Hoax of the Privatization Movement and the Danger to America’s Public Schools.” Damon, whose mom, Nancy Carlsson-Paige, taught a few generations of teachers while a professor at Lesley University, introduced Ravitch to a crowd of students and teachers at California State University Northridge. . . . Closer to home, Luxe Boutique owner Cecil Elrod hosted a fashion show at the Taj Hotel featuring leather, cashmere, and, yes, fur coats. Boldfacers on the runway included Bill Belichick’s significant other Linda Holliday, Jerod Mayo’s wife, Chantel, LaVar Arrington’s wife, VaShonda, party planner A.J. Williams, Raina Patricia, wife of Pats defensive coordinator Matt Patricia, and furrier Mary Kakas. Among those in the audience were Marilyn Riseman, Bill Emery, Marjorie Clapprood, and Chris Spinnazola.