This non-profit provides free resources to teachers and to casual coders. They started the Hour of Code, and now have literally hundreds of short tutorials and mini-games designed to get people interested in coding (which is much easier to learn these days). They also have a ton of online curriculum for teachers for all grades, from kindergarten all the way to a high school course, complete with lesson plans, online tools, videos, handouts, offline "unplugged" activities, assessments, progress tracking? And more. They also offer free and subsidized training for teachers that is really good.
This site is one of the best kept secrets on the web!