The Khan Acadamy, www.khanacademy.org, contains over 2,700 videos and 260 practice exercises for people interested in learning anything from arithmetic to physics to investing. As they say, "Watch. Practice. Learn almost anything for free.” Though this site is heavily focused on science (including healthcare and medicine), math, history, and economics, there are also videos for general SAT and GMAT prep. Take a little time to check it out; we guarantee that you will learn something!