DataSource.ai - Community-funded data science tournaments

Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.

Machine Hack - Machine Hack is the Machine Learning competition and assessment platform that makes it easy for data scientists, engineers, and business professionals to learn, compete, and get hired.

Noizio - Feeling that the noise of the big city is too much for you to bear?

Driven Data - DrivenData hosts data science competitions to build a better world, bringing cutting-edge predictive models to organizations tackling the world's toughest problems.

zenmix.io - Ambient background sound generator