1. Top Coder
This is the biggest competitive software development community in the world. It has members from over 200 countries and the number of members spread over 200,000. You can find contests in Java, C# and C++.
This website originates in India and has over 25,000 members. It gets membership from all over the world though and hosts events, contest and training for them.
This is a website by the World Bank, inviting developers to create innovative tools and apps by making use of the data that it has collected through its Open Data Initiative.
Facebook’s Engineering Puzzles are available on the company’s careers page. It can be a good opportunity for you to land a job at the world’s biggest social network, which has been known to have one of the best work environments.
This website hosts monthly contests. It has been created by a gaming company looking to promote HTML5 mobile games using these contests.
This website hosts two programming contests every year. Interestingly, it doesn’t ask you for the code that you have written and you just have to come up with the solution. Hence, a programmer can use any tool that they want to solve the problems
This website contains a number of programming problems that can be solved using various programming languages.
This is a well known website amongst programmers, which hosts challenges in computer and mathematics.
As evident from the name, this website hosts challenges to be solved using the Python programming language.
Original Source: http://efytimes.com/e1/fullnews.asp?edid=132115