1. Learning Vim while playing a game

  2. CheckIO is a web site with a mission: To teach JavaScript and Python coding skills through a game-playing interface. It is designed to teach new skills or improve existing skills through completing challenges.

  3. Achieve code mastery through challenge.

  4. Join over 2 million developers in solving code challenges on HackerRank, one of the best ways to prepare for programming interviews.

  5. CodeFights provides a fun and competitive way to practice your coding skills, learn new talents, and prepare for interviews.

  6. Learn to code JavaScript by playing game.

  7. Coderbyte is a place built for anyone to practice and perfect their programming skills.

  8. CodeEval is platform for hosting coding challenges which has over 20,000+ competitive developers.

  9. Project Euler is a series of challenging mathematical/computer programming problems that will...

  10. The developer testing tool that helps you make safer recruitments.

  11. The Topcoder home page has received a slick new makeover that lets new customers quckly login, discover the power of our community, and launch challenges.

  12. Geektastic is a platform that manages peer reviewed code challenges supported by a community of qualified software engineers.