I just made githubcloneall. It clones all the public GitHub repositories of a user, and for the 89 public repositories I have it can clone them all in approximately one minute.

I use throw-away containers for my development environment and so often find myself needing to clone several repositories. This gets me all my repos in less time than if I was to clone just 3-4 repositories.

Download: github.com/leighmcculloch/githubcloneall