Related sites:

• worldchallenge.org

  World Challenge | Live a Better Life, Make a Better World Through Jesus Christ

  

• pythonchallenge.com

  The Python Challenge

  

• world-challenge.com

  SRO Motorsports America (formerly Pirelli World Challenge)

  

• the-challenge.org

  The Challenge | Building a more integrated society

  

• challengerseries.net

  ChallengerSeries

  

• spaceappschallenge.org

  NASA International Space Apps Challenge

  

• 30dayfitnesschallenges.com

  30 Day Fitness Challenges - Exercise Workouts & Video Tutorials