Nourish Interactive.  Lots of information sheets, games, activities for parents, students, teachers
USDA National Nutrient Database
Recipe Nutrition Calculator
Kidnetic
Choose My Plate Kids' Place
Jamie Oliver's Food Revolution

Sugar Stacks
TEDed: How Sugar Affects the Brain
TEDed: Sugar Hiding in Plain Sight
TEDed: What is Fat?
TEDed: How do vitamins work?
TEDed: What's wrong with our food system?
Untamed Science: Why we crave sugar (on YouTube)