"The Master" is about a religious movement launched after World War II, but it's not a Scientology story. Don't be ridiculous! The movie just features someone who looks like Scientology founder L. Ron Hubbard, who's wife has the same name as Hubbard's wife, who came up with the movement while he was at sea like Hubbard did ... but it's not the untold story of Scientology. Really!
"Argo" (pictured) really is the untold story of a scheme to rescue hostages from Iran by disguising them as members of a film crew. It veers between dark hilarity ("Do you have a better bad idea?" "This is the best bad idea we have, sir -- by far.") and incredible tension ("I think my little story is the only thing between you and a gun to your head.") It's a must-watch.