Yale University in Connecticut offers many free “Open Courses” online. The courses include twenty-three 50 minute lectures and assignments. The lectures are available for download, online, in PDF format, and MP3. Some course subjects include Music, History, English, Economics, History of Art, and Philosophy, and there are many more.
Harvard has Open Courses online as well. They offer a number of courses Computer Science, Shakespeare, and Mathematics. Each course has about 10 to 15 lectures available to download or watch in a variety of ways. Some of these courses include assignments.
Khan Academy is very useful for learning about specific things by watching videos on them. Khan Academy has videos and practice problems on many subjects including Math and Science.
Hillsdale College is adding more content to their online course list. The courses include ten 45 minute lectures, quizzes, readings and Q&A sessions. They’re courses include Economics 101, Constitution 101 and 201, The Great Books 101, and History 101 and 102.