This is a busy year for Sarah Polley. Her film Take This Waltz is now in release in the US and now she has a documentary premiering at Venice and Toronto.
Here's the opaque description from the National Film Board of Canada site:
Oscar®-nominated director Sarah Polley offers up a genre-twisting film that playfully excavates layers of myth and memory to reveal the truth at the core of a family of storytellers. The film premieres at Venice Days film festival, followed by a Special Presentation at the Toronto International Film Festival in September.