Speedcube - A simple and elegant Rubik's cube solve timer
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Linia - You will never look at colors the same way...
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Colorcube - Turn pieces and blend colors in this minimal puzzler
Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.