Potterheads love their talking spiders, scolding letters and giant snakes. And they’ll also love two screenings of “Harry Potter and the Chamber of Secrets” in high definition with the Richmond Symphony performing John Williams’ score, always a plus for any film. The Saturday screening is at 7:30 p.m. and there’s a Sunday matinee at 1 p.m. $52.50 to $82.50. altriatheater.com.