Director Mark Wexler embarks on a worldwide trek to investigate just what it means to grow old and what it could mean to really live forever. But whose advice should he take? Does 94-year-old exercise guru Jack LaLanne have all the answers, or does Buster, a 101-year-old chain-smoking, beer-drinking marathoner? What about futurist Ray Kurzweil, a laughter yoga expert, or an elder porn star? Wexler explores the viewpoints of delightfully unusual characters alongside those of health, fitness and life-extension experts in this engaging new documentary, which challenges our notions of youth and aging with comic poignancy. Begun as a study in life-extension, How To Live Forever evolves into a thought-provoking examination of what truly gives life meaning.

• Documentary