According to 2K’s PR representatives, Civilization: Beyond Earth is now available to pre-load on Steam prior to Friday’s release date. That means you can get all the 1s and 0s downloaded in advance of the game’s launch.
The system requirements demand 8GB of hard drive space, so I’d imagine that’s roughly what the download size will be. Obviously you need to have purchased the game in order to download it early.
In addition to being able to preload Civilization: Beyond Earth, 2K and Firaxis are making Civilization V free to play around with on Steam until 23 October. You won’t get to keep it in your library beyond that date, but I suppose if you need something Civilization-related to keep you occupied prior to Beyond Earth then it will serve that purpose.
If you missed the release of the introductory cinematic, then you can see that below.