While a lot of the fun in Game of Thrones takes the form of palace intrigue in the capital, King's Landing, there's usually a good long trek of one variety or another happening. There's Arya's escape from King's Landing after her father's death, Bran's journeys in the North, Daenerys's slave-freeing tour in Essos, Jaime and Brienne's fraught travel to King's Landing in season three, among many others.
It can be a lot to keep track of. So, like a genius, series superfan serMountainGoat created an interactive map where you can track the locations of all major characters. Best of all, the map lets you see where everyone is down to the episode (or, if you prefer, book chapter), so that you don't spoil yourself looking at the map. You can access the whole thing at quartermaester.info; below is a GIF showing Arya's path from season one to three, which is a good example of the kind of thing you can do with the map:
Thanks to The Guardian for the pointer.