Free ways to learn something
Learning isn't just for eggheads and children. Class Central will get you back in the classroom without the awkward self-discovery and crippling student debt. You'll have access to recordings of full college courses, plus syllabi.
补课不可仅捆绑于书生和黄口小儿。 Class Central能帮你还归讲坛中，除了然麻烦帮你形成刁难的人家自认为之旅或者令各位不堪重负的大伙儿债权人。 你都有次数获得完整无暇的上学方法事件，另有加上教育纲要。
Basically the same as above, except this one has you in a specific set of hallowed halls, namely Yale's. Other colleges have similar programs, but this one stands out.
Coursera features classes put together specially for the platform by professors, complete with assignments and opportunities to interact and collaborate with other students.
Code Academy will teach you the joys of coding and potentially the joys of making a bunch of money.
Duolingo is a great way to learn a language and is built around mini-lessons in a game-like format you might even enjoy. It's for sure a more productive way than Candy Crush to spend a train ride.
MusicTheory.net is the perfect way for a beginner to learn how music works or to just brush up on the basics.
Free movies and books
Open Culture has just about everything, including textbooks, movies, audiobooks, and ebooks.
The aptly named Documentary Heaven has a bunch of free documentaries.
Project Gutenberg features over 56,000 free books (available to read online and often as Kindle downloads). Most of these have entered the public domain, so if you're interested in a throwback, you'll find it here.