Watch Grass for Free: How to Stream the Movie Online at 123Movies. . Marijuana is the most controversial drug of the 20th Century. Smoked by generations to little discernible ill effect, it continues to be reviled by many governments on Earth. In this Genie Award-winning documentary veteran Canadian director Ron Mann and narrator Woody Harrelson mix humour and historical footage together to recount how the United States has demonized a relatively harmless drug.