Shameless but relevant plug: I'm building an app that uses a lot of these principles to help you learn. It's called Lernabit.
The way it works is you use the app to create a 5-10 minute long audio lecture. By teaching others, you improve your own understanding of the subject. Then those audio lectures become freely available for others to learn from it. And because the lectures are in audio format, they are accessible to busy people. You learn by teaching others, then we give a portion of the revenue to charities focused on education. It is currently available online and on Android.
Judging by your comments, it sounds like something that might interest you, so I would love to hear what you think.
Disclaimer: I built and own this app.
I've built an app that is designed for people who learn on their own without a structured classroom setting. It's called Lernabit, and it is a digital notecard app that helps you remember what you learn. When you learn something new, you can create a notecard in Lernabit, then Lernabit will let you know when it is time to review it. You mark the review as "Complete" and it automatically schedules the next review time. You can also share your notecards with other people (or keep them private) and explore notecards from other people and add them to your own review list.
I use it whenever I learn something interesting from books, documentaries, and museums, or anywhere else. Whenever I get a few minutes of free time, I open the app and review a few notecards. It is a lot more productive than scrolling through Twitter.
I'm happy to answer any questions you might have about it.
Shameless plug: I've built a note taking app specifically designed for learning. It is called Lernabit. When you take notes with Lernabit, it will automatically remind you when it is time to review them. Then you click "Done reviewing" and it schedules the next review time. Instead of your notes just being buried and forgotten, they gradually work their way into your brain.