Playground lets you try out .emacs.d configuration repositories. The basic idea behind Playground is to create an isolated directory called a sandbox and make it $HOME of Emacs. Playground allows you to easily experiment with various Emacs configuration repositories available on GitHub, while keeping your current configuration untouched (almost, except for stuffs related to Playground). It can also simplify your workflow in Emacs by hiding irrelevant files and directories existing in your home directory.