By Jake Coyle/The Associated Press NEW YORK (AP) — Still haven't seen "Barbie" or "Oppenheimer"? This Sunday, you'll be able to catch up for $4 a ticket in movie theaters nationwide. Theater owners announced Monday that the second annual National Cinema Day will be held Sunday, Aug. 27. For one day, all movies — in all formats and at all showtimes — will be $4 at participating theaters. More than 3,000 theaters are participating, which accounts for most of the cinemas in the U.S., including the leading chains AMC and Regal. It's the second straight year theaters are trotting out…