Any other knowledge junkies?
If there are any other people out there who love learning as much as I do, you might want to know about Khan Academy. It's the only website that I like as much as Duolingo. It has thousands of videos on math, science, finance & economics, history, art history. There are also hundreds of practice exercises, points, badges, and other fun things. Check it out at www.khanacademy.org. Share your favorite educational websites below :)
I have compiled a large list of websites that I believe are excellent sources to learn from. I hope everyone enjoys them as much as I do.
https://www.khanacademy.org - An ever-growing library of over 4,000 videos on a large variety of subjects, including arithmetic, algebra, calculus, physics, chemistry, astronomy, history, medicine, economics, art, and many more. There is also a fantastic exercise engine which allows you to practice mathematics. The only negative of the site, in my opinion, is that there are no videos on languages, however I'm sure that someday in the future the Khan Academy team will begin lectures on languages as well.
http://ocw.mit.edu - If the content of Khan Academy is too elementary for you, this is the place to go. MIT's OpenCourseWare hosts an unbelievable number of course materials, where you will engage in all the rigor and stress that any student at MIT has to endure. If you are looking for a free college education, this is the way to go.
http://www.open.edu/openlearn/ - Though I haven't visited this website nearly as often as MIT's OpenCourseWare, I imagine this is the Open University's take on the same idea that MIT's OpenCourseWare has.
http://www.ocwconsortium.org/ - MIT and The Open University are not the only schools hosting free online course materials. The OCW Consortium allows you to search for any course materials from most of the major OpenCourseWare schools. OCW Consortium is a way to compile all of the OpenCourseWare into one search engine so you can find exactly what you are looking for no matter the school.
http://www.brightstorm.com - Brightstorm is not a free service. I haven't looked into what the costs are for their resources, because I am uninterested in paying for them. I have, however, watched a handful of their videos, and they are actually pretty solid. If you don't want to pay to watch the videos, visit the YouTube channel "brightstorm2" where it appears that most of their videos are freely available.
http://www.academicearth.org/ - Academic Earth is pretty much the college version of Khan Academy. The library of videos is not nearly as large as Khan's, but it hosts free lectures from some of the world's greatest professors teaching at the world's greatest universities. It's almost too good to be true.
http://thenewboston.org/ - TheNewBoston is a YouTuber who has uploaded a wide variety of tutorials on many interesting subjects. From what I've seen, he has tutorials for building a go-kart, game programming in Java, introductory programming in Java, elementary algebra, introductory chemistry, introductory biology, introductory physics, and it seems that recently he has been starting a tutorial on how to make beer. The guy has a wide variety of knowledge, and it would be a mistake to ignore his resources.
http://www.ck12.org - CK12 is one of my favorite websites for elementary subjects. They have a wide variety of free textbooks, (which they refer to as "flexbooks") on many basic subjects, such as arithmetic, life science, biology, physics, algebra, history, chemistry, and so on.
http://k12videos.mit.edu/ - MIT's K-12 videos really are some of the most interesting ways to introduce concepts to learners.
https://www.edx.org - edX is quite possibly the future of secondary learning. A number of top universities have teamed together to create edX, in which they offer real online courses from real university professors completely for free. You will be required to do homework, and pass tests, and if you can manage to endure the rigors with a high grade in the course, you could be awarded a certificate of completion for the course. I didn't achieve a certificate, but I did endure the 6.00x course for a few weeks, and wow, I was blown away. It's amazing that this opportunity is being given to us, and entirely for free.
http://en.wikiversity.org - Wikiversity is in many ways like Wikipedia, but in a curriculum form. Imagine if instead of simply an encyclopedia, Wikipedia also functioned as a school. Wikiversity is just that.
http://www.saylor.org - In my opinion, the most underrated of all the websites I've posted here. The Saylor Foundation has nearly 300 free courses ranging from elementary to advanced levels. Many of their courses are available in iTunes U, so if you are fortunate enough to own an iDevice, be sure to check them out.
https://www.coursera.org/ - Coursera has won multiple awards for their innovative approach to free online learning. Earlier I gave a description of edX as possibly being the future of secondary learning, but I must admit that Coursera is actually far ahead of edX at the moment. They are partnered with many more universities, therefore hosting many more courses. Once again, it's difficult to believe that all of their content is free.
https://www.udacity.com - Udacity doesn't have a large number of courses, but the few that they do are certainly note-worthy. Check the website out, and if you can't find anything you are interested in learning, check again in a few months. This website has a bright future, all they need is more content.
http://www.codecademy.com - I like to think of Code Academy as the Duolingo of computer programming. You go to Duolingo to learn a language, you go to Code Academy to learn a programming language. Check it out if you are interested at all in programming.
http://thinkquest.org/pls/html/think.library - I haven't visited this website much, but this is the description as it reads on the website "Over 8,000 websites created by students around the world who have participated in a ThinkQuest Competition."
http://www.memrise.com/ - Memrise is another website sure to have a bright future. If you are looking to memorize anything, this is the place you want to go. You can create your own courses if you like, or take a course that has been created by another member. Memorize the periodic table of elements, or words from a foreign language. Memorization is a key component of learning, and no method does it better than Memrise.
http://www.ureddit.com/ - uReddit seems to be a community of people teaching other subjects to people for free. I haven't checked it out much, but I believe it is certainly worth listing.
http://www.cosmolearning.com/ - Another website that I haven't used much, but Cosmo Learning appears to be another large library of free lecture videos.
http://www.sophia.org/ - Sophia is a wonderful collection of learning resources.
http://learni.st - Learnist is a social way to learn, allowing people to compile resources as they find them on the Internet into one giant learning resource for all people to view and use.
Amazing list! Really appreciate you taking the time to put it together. I have been using https://www.coursehero.com/sg/ and https://modernstates.org/ for some time now. They are both similar to Khan and other the OER's you mentioned. I have been using Course Hero in combination with Modern States to test out of general education classes at my college.
Course Hero and Modern States both offer lessons for subjects ranging from STEM to Social Sciences. I really like Course Hero because the study guides have been reviewed by university professors and subjects are broken down into easily digestible sections filled with infographics, tables, videos, vocabulary words, and reading recommendations. Some sections also allow you to test your knowledge with practice problems.
I like it in a way. As was pointed out it is strictly memorization from what I have seen.
I'm doing their French thing which is repetition of words seemingly chosen at random. So far. There is no comments section to ask for clarification or such. Used in conjunction with Duo it can be helpful.
Some courses, at memrise at least, seem to be made up by just anyone who thinks they have something to contribute. That sounds nice and all but it can certainly make for an uneven quality to the courses they offer.
I'musing Memrise to keep hold of some of my Mandarin, and I like that it's straightforward vocab/sight drills, because I want to focus on French here, while keeping Mandarin from falling apart completely...can't find time to do both at all intensively.
In short, I like it in combo with Duolingo, but in my case I'm using it for another language entirely...might try out French on Memrise; we'll see.