The Great Courses offers DVD, Audio CD, and streaming courses taught by experts in their fields in a variety of subjects, including art, history, math, and science. These are not traditional courses in that there is no homework or tests. It is education purely for the sake of learning. They are geared for adults, but could certainly be used as part of a high school curriculum.
To find out more, please visit http://www.thegreatcourses.com