is an educational non-profit organization committed to improving access to education. MITE (pronounced "mighty") manages a range of projects from establishing systems for the development and distribution of open educational content to efficacy studies and other educational research. Two of MITE's cornerstone projects are the National Repository of Online Courses (NROC) and the MacArthur Series on Digital Media and Learning.
One of their services or enterprises is Hippocampus
A free, public website for high school and college students that offers NROC content.
I haven't poked around much but it looks interesting.