Even if you are not in school, it is still a great idea to continue your learning. It can help you keep good studying habits, broaden your horizons, and even look good on your resume. Beyond that, it is fun to learn more about something you are interested in. When you do not have to worry about credit hours, you have a lot more freedom. These are my favorite sites.
Coursera: This has a large number of college courses from accredited universities all over the world. The classes are free, but you can choose to pay a fee to receive a certificate of completion.
Khan Academy: This started out as math tutorials but now includes economics, art, history, and college preparation. The videos are short and can be watched in whatever order you choose. You earn badges for different activities, making it feel like a game.
Duolingo: This is a free language learning platform. The best way to see how it works is to try it for yourself. Languages available include French, German, Vietnamese, Hebrew, and many others.