Take classes online from Yale, MIT, Tufts and other respected institutions for free.
UPDATE: Some of the schools have moved the pages for some of the courses, and the OEDb hasn't updated them on their site yet.
I checked every link listed. The majority still point to the proper course.
Some have moved and provide a link to the new page. The links all led to the the new URL of the same class.
Some have error messages. In the case of error messages, check the home page of the University's Open Course section.
I've listed the links to each University's Open Course site. They have the current class listings.
Some of the links (all at Utah State University) wanted a name and a password. If you run across one of those, check the the Open Course home page. END UPDATE
The Online Education Database has put together 200 online classes from these and other institutions.
You can take as many as you like that interest you - there seems to be no limit and I couldn't find any strings attached in any of the material I've looked at.
Topics cover a very wide range - everything from Natural Science to Law and Politics.
If you want to learn three-dimensional modeling and animation using the Open Source software Blender, there's a course for that.
Learning and applying HTML, Network Security, Flash, Quantum Mechanics, First Year Chinese, Modern Poetry, and Implant Dentistry are some titles of other classes being offered.
The Visual Arts seem to be missing. I would like to see classes in that area appear in the catalog.
Aside from the missing Visual Arts, if you are a life long learner (of any age) there is a lot to keep you busy.
The Beginning Online Learning page has some wonderful articles and resources. Geared specifically towards learning, there are some gems that anyone can use.
The site is geared towards helping people find financial aid for college and is a bit on the commercial side in places. The class listings segment is relatively free of advertising and worth a few ads.
University Open Course Home Pages:
Tufts Open Course
UMass Boston Open Course
MIT Open Course
Utah State University Open Course
Yale Open Course
Notre Dame Open Course
UCIrvine Johns Hopkins Open Course