I recently came across an article from a 2013 issue of School Library Journal, Hank and John Green: Using Their Powers for Good, and discovered some wonderful web resources created by the two brothers. Now, if by chance you don't have any teens at home, or never visit the library or a bookstore, or never go to the movies, then you may be unfamiliar with John Green. John is the author of several well received teen novels, including the wildly popular, "The Fault in Our Stars."
Together, the brothers have three YouTube channels that present videos on a range of topics. Take a look and see if you (or your teen) might enjoy them.
CrashCourse: 8 classroom courses including history, psychology, and literature.
SciShow: Exploring science news, concepts, and history.
vlogbrothers: Random musings on a variety of topics.