Get a free education online: Learning at the library
The Wikimedia Foundation's quest to bring crowdsourced knowledge to the masses doesn't begin and end with Wikipedia. The organization also funds Wikiversity, a project "devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from preschool to university, including professional training and informal learning."
Wikiversity holds a wealth of information categorized into education level, general topics, and subtopics, all of which can be searched using a number of different filtering methods. To be honest, it's a bit overwhelming and difficult to navigate, especially if you're used to Khan Academy and YouTube Education's well-designed sites.
It's worth the trouble, however. Since it's maintained by passionate contributors, Wikiversity espouses on a much wider range of topics than most other online education resources, ranging from basic reading, writing, and arithmetic to oddballs like stellar evolution, dentistry, and "Media information cognition." There's a lot of stuff here, folks, and it's ambitious to say the least. The site even offers resources in line with what you'd find at a traditional school, such as curated courses with progressive learning schemes, assigned Wikibooks reading, handouts, presentations, and essay ideas.
Unfortunately, the ambitious crowdsourced design sometimes bites off more than it can chew. While some of the courses and lessons offer polished materials of university-level quality (check out Historical Introduction to Philosophy!), a large number of the courses and individual pages lie dormant and half-finished, especially if you delve into niche topics. Also, while most of the resources here are fully legit, keep in mind that schools typically don't allow Wikipedia as a source for a reason.
Our recommendation? Scope out a course before you fully invest your energy in it, and if you're looking for a detailed education on a topic, stick to the courses found in the Completed Resources and Nearly Completed Resources lists.
Como se dice "Learn a New Language" en Español?
Aspiring world travels don't need to invest in costly language courses to learn a second tongue; the San Francisco Public Library offers its patrons access to Rosetta Stone Online Language Lessons for the low, low price of absolutely free. Rosetta Stone software normally costs hundreds of dollars.
To take advantage of the amazing offer, sign in here. After you enter your PIN and the barcode number on your library card, you'll be asked to create a Rosetta Stone Online account. BrokeAssStuart reports that full 19-unit courses are available in Mandarin, French, Hebrew, Japanese, Korean and Spanish, while primers in English, Italian, Greek, German, and Russian stick to three-unit tutorials.
The goodness doesn't end there. Any California resident can swing by a San Francisco Public Library location and sign up for a library card, even if you don't actually live in the city. Plus, the tutorials can be accessed by any computer with an Internet connection—not just PCs at the library proper.
Update We've been told that the Rosetta Stone program is no longer available through the SFPL, however, the Library still offers language learning through the Gate PowerSpeak and Mango Languages programs, which you can access here.
Kicking it old skool, new skool style
Finally, don't forget you're at a library. Read a book! Or rather, read an ebook! Online services like Project Gutenberg, Textbook Revolution, the Library of Congress and the aforementioned Wikibooks all offer awesome freely downloadable titles, though they can be a bit dated.
Most libraries also let their patrons check out more current ebooks to their ereaders, if you have one. The New York Public Library, for example, offers over 30,000 ebooks, a great many of which are modern titles.
You're only getting started, Padawan
What, you've learned all you could from Khan Academy, taught yourself Spanish, earned a certificate in programming autonomous automobiles and even brushed up on astrophysics at Wikiversity? You must be on a first name basis with your librarian. Fortunately, the options we covered are only a small fraction of the free resources available for autodidactic learners.
If you're looking for a bigger challenge, check out Coursera, Academic Earth, Google Code University, or even the University of Reddit. (Seriously!) Heck, you can even take free online courses in theology. There's a whole world of information available at your fingertips down at the local library. Take advantage of it!