NOTE: This Org is no longer accepting invites. They are now going to the EpicGames organization. See this form post for more details.
Epic Games
houses repositories associated with the UnrealEngine
Unreal Engine for game development is free to get started (a 5% royalty only kicks in when your title earns over $1 million USD)
To access our repositories, sign up for an Epic account at UnrealEngine.com and register your GitHub ID using these instructions.
After that, you can find the Unreal Engine Repository here:
(Note that you must be signed into GitHub for these links to work.)