Khan Academy – Over 3,200 videos that cover topics ranging from arithmetic to physics, finance, and history. Also includes a number of computing tracks, including Hour of Code programs. Learn what you want, when you want, at your own pace.
Technology
Stanford Engineering Everywhere
Stanford Engineering Everywhere (S.E.E.) offers some of Stanford’s most popular engineering courses including iPhone App Development to Artificial Intelligence: Intro to Robotics.
edX
edX offers over 650 courses in computer science, the humanities, and math, with over 1,700 faculty and staff from the likes of Harvard, MIT, Berkley, Caltech, and the Sorbonne teaching and discussing topics online. Began as collaboration between Harvard and MIT to bring some of their signature courses to anyone with a computer.
MIT OpenCourseWare
Access materials from over 2,000 courses from the Massachusetts Institute of Technology, including courses in Technology, Science, Economics, Mathematics, and Law.
Code Academy
Uses simple exercises to build programming and Web development skills. Courses include Make a Website, Make an Interactive Website, and languge courses in HTML & CSS, JavaScript, PHP, and more.