I don't know if anyone else here uses this site but I really enjoy it. I try to spend at least a few hours each week taking a lesson on something. I have done a lot of the math and history. Its free and a good way to spend a few hours when you have time. I do it on the computer and have it on my tablet so I can use it anywhere I have a internet connection. The app I have on my android tablet is called "S Educate" and can be found at google play.
"The website 700 micro lectures via video tutorials stored on YouTube teaching mathematics, history, healthcare, medicine, finance, physics, chemistry, biology, astronomy, economics, cosmology, organic chemistry, American civics, art history, macroeconomics, microeconomics, and computer science."
I know that said 700 videos but I read some where else that now there or over 3000.