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Here is decades' worth of knowledge freely available online for those who love to learn. Links that fit under multiple categories are listed only once.

What are your favorite sites to learn from? What sites would you add to this list?

CONTENTS:

I. Top Picks
II. Universities and Higher Education
III. General Collections
IV. How-to & DIY
V. Studying with Peers
VI. Online Books, eBooks, & Journals
VII. Computers, Software, & Programming
VIII. Science & Math
IX. Logic, Words, & Memory
X. Languages
XI. Music
XII. History
XIII. Business, Finance, & Investing
XIV. Food, Nutrition, & Cooking
XV. Survival Tips
XVI. Other

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I. TOP PICKS

Khan Academy
http://www.khanacademy.org/

Academic Earth - Online courses from the world's top scholars
http://academicearth.org/

TED - Technology, Entertainment, & Design
http://www.ted.com/

MIT Open CourseWare
http://ocw.mit.edu/courses/

Stanford Engineering Everywhere
http://see.stanford.edu/see/courses.aspx

Open Yale Courses
http://oyc.yale.edu/

About U. - Collection of free online courses from About.com
http://u.about.com/

Wikiversity
http://en.wikiversity.org/wiki/Wikiversity:Main_Page

YouTube EDU

The Open University - Study at the OU
http://www3.open.ac.uk/study/
http://openlearn.open.ac.uk/

University of the People
www.uopeople.org

University of Reddit
http://ureddit.com/

Open Culture - The best free cultural & educational media on the web
http://openculture.com/

VideoLectures - Exchange ideas & share knowledge
http://videolectures.net/

CosmoLearning - Free educational website with thousands of courses & documentaries
http://www.cosmolearning.com/

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II. UNIVERSITIES & HIGHER EDUCATION

Lecture Fox - Free university lectures
http://lecturefox.com/

More Open Courses:

Open Courseware Consortium
http://www.ocwconsortium.org/

Harvard Extension School - Computer Science & Technology
http://computerscience1.tv/2010/spring/

Johns Hopkins University
http://ocw.jhsph.edu/

Kaplan University
http://ocw.kaplan.edu/...