With free educational content available online now more than ever, you can master almost any course - from basic arithmetic to complex algorithms - without ever setting foot in a classroom.
Khan Academy offers a free online collection of more than 1,800 videos on mathematics, science, history and economics. The short, simple tutorials are taught by project founder Sal Khan, whose ability to simplify complicated material makes the lessons ideal for younger students.
With several hundred university-related channels and thousands of free educational videos, YouTube EDU is a university of the people, as it can be attended at your own pace and according to your personal interests -- and without the pressure of grades! Entire courses from such universities as Harvard, Yale and UC Berkeley are available to watch immediately.
iTunes U features more than 250,000 free lectures, videos, films and other resources. You can download entire courses and watch or listen to them on your iPod, iPhone or other capable device.