Challenges/contests
Coding Game
A new competition every month or 2 months.
You're free to choose the language you want. Be fast with beautiful code!
Web Site
Top Coder
A crowdsourcing website for developpers and entreprenors.
Find the best in every domain (data science, programming, design) to build your project or be the best and earn money!
Web Site
Kaggle
Data Science contests.
You can earn money there too!
Web Site
Code Race Me
Code contests.
Web Site