Minecraft + "Game of Thrones" = WesterosCraft
WesterosCraft is a community project to build the continent of Westeros in Minecraft. For the uninitiated, Westeros is where much of the action takes place in the A Song of Ice and Fire books (ahem, or on TV as Game of Thrones). There are other continents in the fictional world, but this is a good one to start with.
The scope of the project is enormous; over several years, the Westeros map has been built up to cover about 500 square miles—and it's only 63% complete (that link is amazing, by the way—it's a Google Docs spreadsheet showing the various locations, completion status, and so on). Review the project FAQ for more details.
Here's a glimpse at what's going on in this world. It's absolutely stunning:
If you're even vaguely interested, check out the WesterosCraft YouTube channel; my favorites are the "WesterosCraft Walks," like this walk through Casterly Rock (don't miss the rookery starting around 9:30...especially looking out the windows):
And if you're a Minecraft user, of course you can visit Westeros. Dude.