Some films should never have been made. They are too unsettling, too dangerous, too challenging, too outrageous and even too badly made to be let loose on unsuspecting audiences. Yet these films, from the shocking Cannibal Holocaust to the apocalyptic Donnie Darko, from the destructive Tetsuo to the awfully bad The Room, from the hilarious This Is Sp?]nal Tap to the campy Showgirls, from the asylum of Das Cabinet des Dr. Caligari to the circus of...