Befront - Learn UX/UI design skills in practice with bite-sized tasks
UX Challenges - Done reading about UX? Start doing it.
Hyper - Extensible, cross-platform terminal built on open web standards.
VUIchallenge - Daily challenges to improve your voice design skills
Frontend Mentor - Supercharge your front-end skills by building in a real-life workflow. Solve real-world HTML, CSS and JavaScript challenges whilst working to professional quality designs.
Herd - A marketplace for online support groups.