I've been watching this great video from a professor about EM waves:
It's really something that such high-quality instruction can be had for free these days. I'm just sitting in my office, learning from this guy. No tuition or scholarship needed, and I can learn about whatever I'm interested in, whenever it's convenient.
I saw this other video, just before, about visualizing the Fourier Transform. It was pretty good, too:
There are so many neat things to think about, it's almost overwhelming.
EDIT: Thinking more about this... The people that put out this kind of material understandably request compensation, sometimes. The cost of sufficiently contributing to these efforts is maybe 1% the cost of formal education. The more the world moves in the direction of needing people who can do things, as opposed to just meeting academic standards, the more this will become how things are taught. It's the way of the future, the way of the future...