A Journey Through Middle Earth
I know it's a promo piece for the new Hobbit movie (of which, I don't know why they split it up into multiple parts. It's not like it was a long book to begin with), and it's a glorified powerpoint presentation, but hey, it's still kinda cool.
Google and the Hobbit movie people made a cool info site that's a huge mashup of different web technologies to let you "journey" around Middle Earth.
It's a Chrome thing, so if you're on Firefox or IE or *laughs* Opera, it won't work as expected.