Having only a casual interest in certain aspects of history, I have found a good way to bone up without a big time investment is to read children's books. This one doesn't go into much detail, because it's aimed at 8 years and up. But it gets the basics. And the pictures are lovely. Before reading this book, about all I knew about Kubla Khan was that "In Xanadu did Kubla Khan / A stately pleasure-dome decree." Now I'm a bit more informed.