Ha, I knew I recognized that name in the domain. Pavel Grinfeld has some great lectures on YouTube, and last I looked, was working on a very useful interactive site for learning mathematics.
https://www.youtube.com/channel/UCr22xikWUK2yUW4YxOKXclQ
I love it, especially the videos on Linear Algebra and Differential Equations. He's an extraordinary teacher, much like Strang, imo.