Khan Academy is an amazing site that contains over 1,600 math, science and history videos designed for “providing a high quality education to anyone, anywhere”. It is created and maintained by Salman Khan, who started the site after remotely helping his niece with her math homework. All the videos on the site are created by Salman Khan and are about 20-30 minutes in length. The site also contains online exercises generated for students based on skill level and performance. Over 35,000 people watch the videos on Khan Academy daily!