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.
UX Challenges - Done reading about UX? Start doing it.
Singscope - See your pitch analyzed as you sing
Vanido - Vanido is a singing coach in your pockets.
Weekly UX Exercise - Receive challenges top companies use to interview designers
User Inyerface - A painful illustration of bad UX