Stories told in the movies are often unearthed from the bric-a-brac of our own lives, since life teems with narratives. For her first documentary, Sarah Polley lifted the veil on a family secret whose revealing caused her and her close ones much, much heartache. Polley ("Take this Waltz") is an Oscar-nominated writer, actress, and filmmaker who's made two feature films about intimate relationships and the challenges faced.