Via Dmitry Podolsky, a series of YouTube videos from Stanford encompassing an entire course by Lenny Susskind on general relativity. I didn’t look closely enough to figure out exactly what level the lectures are pitched at, but it looks like a fairly standard advanced-undergrad or beginning-grad introduction to the subject. (For which I could recommend an excellent textbook, if you’re interested.) This is the first lecture; there are more.
It’s fantastic that Stanford is giving this away. I don’t worry that it will replace the conventional university. The right distinction is not “people who would physically go to the lectures” vs. “people who will just watch the videos”; it’s between “people who can watch the videos” and “people who have no access to lectures like this.” And Susskind is a great lecturer.