Free Online Lectures from Top Rated Universities

Academic Earth features over 1500 lecture videos from MIT, Stanford, Berkeley, Harvard, Princeton, and Yale. Here's a list of subjects:

    * Astronomy
    * Biology
    * Chemistry
    * Computer Science
    * Economics
    * Engineering
    * English
    * Entrepreneurship
    * History
    * Law
    * Mathematics
    * Medicine
    * Philosophy
    * Physics
    * Political Science
    * Psychology
    * Religion

Some of the lecture videos are grouped into courses that contain anywhere from 4 to 50 lectures.
Lectures are searchable by subject, university and popularity.

Clicking on the name of an instructor brings up a page listing the lecture videos related to that instructor.
No credits are given for the courses. You can take as many as you wish and learn as much as you want to.

On each lecture page there are course details and licensing information (mostly Creative Commons), any related resources such a syllabus, and a fun "dim the lights" feature that blacks out everything but the video.
All the lectures can be saved one way or another. Check individual lectures for formats, or check the FAQ. 

If you register, you can save lecture videos under "Favorites" in your profile.

You might lose a lot of time at this site. I did. I was also unsurprised to find that Physics still doesn't make sense to me, and that some instructors still make me sleepy.
I love the design of this website - it is so easy to use and the layout is clean. You can get most places with a few clicks.

Academic Earth