Best Of: 'The Farewell' Director Lulu Wang / The Nocturnal Brain

When Lulu Wang's grandmother was diagnosed with terminal cancer and given three months to live, the family flew to China to see her, but decided not to tell her the prognosis. "I turned out to be a surprisingly good liar," Wang says. Her new film 'The Farewell,' starring Awkwafina, is based on her family's lie.

Justin Chang reviews Quentin Tarantino's new film, 'Once Upon A Time... In Hollywood.'

Neurologist Dr. Guy Leschziner, author of 'The Nocturnal Brain,' says sleep is not a binary state, and the brain can be in multiple stages of sleep at once. That can explain why people sometimes walk, eat, and even have sex while sleeping. He talks about insomnia, medication, and some of the more unusual disorders he has treated.