GitAuth-GH makes the task of backing up your GitHub repositories (both private and public) to another github server automatic.
By leveraging {GitAuth, an open source git-over-ssh auth server}[http://github.com/brownbeagle/gitauth] to do the heavy lifting, gitauth will automatically provide an up-to-date read-only copy of your applications source code, along with synchronized deploy and user keys. Look out in the near future for a screencast introducing it!