As a part of my getting acquainted with Elixir/Phoenix and Elm, I created this app that allows you to play the well-known Concentration (aka Memory) game over the Internet: http://pairs.one/ . It uses Phoenix channels for communication, Redis for state, supports 1-5 players and provides a few awesome visual themes. It requires no registration - just create a new game, share the URL with your opponent, and start playing. With enough interest I might open-source the code (needs a bit of clean-up) - let me know on Twitter!