“I know a lot of films that other people don’t know,” Nan Goldin said when we asked for her Cult Vault. Over the last few years, we’ve mined the obsessive passions of directors and artists all over the world by asking them to share their underground film secrets. Along the way we’ve discovered some brilliantly obscure and unsung treasures, by asking filmmakers we love, who they love: Pedro Almodovar introduced us to his late friend Ivan Zulueta’s 1980 tale of drug addiction and vampirism Arrebato, and Bruce La Bruce gave us Frank Perry’s 1972 Play it as it Lays (“A jaded, realistic portrait of LA’s seamy underbelly that goes a long way toward explaining the Lohans of today.”). There was also Nick Broomfield’s idiosyncractic recommendation of a film entirely about a man trying to escape from a sandpit. Here’s all our discoveries so far….