https://www.codingame.com
Learn to code by solving game situations

https://www.codeeval.com/
More traditional programming challenges gamified

https://codecombat.com/play
Learn Python/Javascript with a game

http://www.jsdares.com/
Navigate robot with simple programming

https://scratch.mit.edu/
Visual programming, interactive presentation creation and remixing other ideas

https://screeps.com/
MMO strategy for programmers (thx Laurent!)

https://vim-adventures.com/
Learn VIM by playing a game 🙂