Today’s guest post comes from Josh Olson, a student at the University of North Carolina at Charlotte. He is also a would-be iPhone app developer.

Whether college is the best of times or the worst of times depends greatly on your professors’ abilities to teach. Some can’t. Fortunately, there are a number of swell digital resources that help you hack your knowledge. Here’s how to learn cool stuff for free.

First, there’s ted.com. This website provides videos from the TED conference—a gathering of scientists, digital gurus, entertainment big-wigs, and Bono. These videos cover an array of subjects, all explained by some of the brightest minds of our time. For instance, in this talk Robert Wright talks about game theory, non-zero-sumness, and his “grimly optimistic” philosophy of history. If you’re taking a music class, you might like Itay Talgam’s talk explaining the art of conducting an orchestra. Or if you’re in physics you have to check out Brian Greene’s excellent explanation of string theory. Astronomy got you down? Listen to Stephen Hawking talk about space aliens. Or if life in general’s got you down, listen to Bill Gates talk about what’s wrong with the world and what we can do about it.

Speaking of Bill Gates…

…if you’re struggling with math, economics, history, or chemistry try Khan Academy. It is a website featuring videos that explain difficult concepts in a clear manner. And they are also free. This relates to Bill Gates because the Microsoft man liked Khan’s work so much that he gave him a heap of cash. Khan continues to add videos and expand into more subjects.

But if you can’t find help in any of the above resources, you can find what you’re looking for on YouTube. There is a lesson series for virtually every subject imaginable there. For example, Andrew Furmancyzky has created a series of music theory lessons (with homework!). There are more guitar-lesson vids than you can shake a stick at. And there are fun cartoons on genetics, among other things. These are just a few examples of YouTube’s wealth.

How do you supplement your knowledge outside the classroom? Let us know in the comments!