Well, yeah, that's what this is about. My pals (they're not my pals) the Vlogbrothers have a new YouTube channel, and it's all for education: Crash Course. Each brother has a subject, and they come to you each week to teach you something new.
John teaches world history, starting with the agricultural revolution. Woo! I have watched all the videos, and I don't remember everything he said, but I do remember that the Mongols are the exceptions to every rule. These videos are probably handy if you spent all night reading a nice book like The Return of the Native and need a quick refresher for that quiz you're going to have in class.
Hank teaches biology, and I'm pretty sure it's less crash-y than world history, just because it takes less time to explain the octet rule when you don't have to make sure your students understand the political and economic implications of electron sharing. (There aren't any, you see.)
So, there you are! Crash Course! Study up on what you learned in class, or just relearn what you forgot oh so many years ago. An educated populace is a good populace.
You can watch more videos or subscribe to Crash Course at YouTube.