I really like the look of Codeplace as a way to start or further your web development skills. I came across the site on ProductHunt, and I liked what their CEO had to say:

Codeplace’s objective is to make you ready for your next web development job. Our belief is that the more you practice building real web applications, the more comfortable you will feel as a developer. That’s why our library mainly consists of code projects such as a Project Management Tool, 2 Sided Marketplace, Social Network, Automated Social Platform, Dating App and More. We’ve also just launched our new Web Development Path this week. Let me know if you have any questions 🙂 [Tiago Martins via ProductHunt]

Codeplace features tracks for beginners and seasoned developers. It looks like a great way to level-up!