Scratch
Developed by MIT, Scratch is more than just a game. It is a graphical programming environment where kids can create games and animations using drag-and-drop programming events. While Scratch may seem a little intimidating at first, once you learn the basics of the system, it is fun and easy to use. The website includes an online community of Scratch developers who share their games and creations online, so you can also play lots of free games at the site.
CodeCombat
CodeCombat is an amazing, graphically rich programming game that teaches typed code. Students have their choice of coding with Python, JavaScript, CoffeeScript (an experimental “nicer” JavaScript syntax), or Lua. The game looks and feels like a fantasy role-playing game, but you type in code to get the character to do what it needs to do. Ample tutorials are included to help prompt the proper code syntax. A free online version of the game is available at the website that can be played anonymously without logging in.