The Lord of the Rings and Hobbit books and films are major events in a world with much more history than what we usually see in popular culture. Tolkien has earned such die-hard fans, in part, due to the fact that his worlds work in a way that's rare in fantasy or science fiction.
It's not just a matter of a bit of culture here and there. Middle Earth has fully fleshed out languages and histories stretching back far from the events of the main texts. This video is a five minute look at the history of the One Ring, and the events that led to its creation.
It makes explicit a few things that were hinted at in Lord of the Rings and the Hobbit, and you don't have to suffer through the somewhat dry nature of the surrounding texts to get caught up. This is like CliffsNotes for a world that doesn't actually exist, and I love it.