The Hour of Code is a global movement reaching tens of millions of students in 180+ countries. Anyone, anywhere can organize an Hour of Code event. One-hour tutorials are available in over 40 languages. No experience needed. Ages 4 to 104.
Launched in 2013, Code.org® is a non-profit dedicated to expanding access to computer science. Their vision is that every student in every school should have the opportunity to learn computer science. They believe computer science should be part of core curriculum, alongside other courses such as biology, chemistry or algebra. Code.org increases diversity in computer science by reaching students of all backgrounds where they are — at their skill-level, in their schools, and in ways that inspire them to keep learning.
Tynker - Tynker is a creative computing platform where millions of kids have learned to program and built games, apps and more. Tynker offers self-paced online courses for children to learn coding at home
Codezilla - Particularly good for kids, Code Monster features two adjacent boxes. One displays code, the other shows what the code does. As you play around with the code with some help from a prompt, you learn what each command does.
Learning to Code: The Best Apps & Services - online article from 9/12/16 (some are fee-based!)