'Heart of Glass' (1976)
In telling the story of a man trying to discover the secret of a late glass-blower's singular creations, Herzog knew he was looking for performances that suggested a slowly building epidemic of insanity in the film's small-town locale. So he did what any inventive filmmaker would do: He hypnotized 99-percent of his cast ... as in literally hypnotized them. (There's a great book on the movie's production that details the complete 411.) To say that this gamble resulted in one of Herzog's more outside-the-box approaches to acting would be putting it mildly, but watch the far-out faces of the supporting players. You absolutely feel as if you're witnessing a population held captive under someone's spell.