March of the Penguins - the yearly journeys of the emperor penguins of Antarctica
Super Size Me - follows a 30-day time period during which Spurlock subsists entirely on food and items purchased exclusively from McDonald's
An Inconvenient Truth - about global warming
Riding Giants - traces the origins of surfing and specifically focuses on the art of big wave riding
Spellbound - follows eight competitors in the 1999 Scripps National Spelling Bee.
Anything by Ken Burns