Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
Pithos - pithos is a daemon which provides an S3-compatible frontend for storing files in a Cassandra cluster.
Kajero - Interactive JavaScript notebooks - create good-looking, responsive, interactive documents.
Keybase Chat - End-to-end encrypted chat built into Keybase
BeakerX - Open Source Polyglot Data Science Tool
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.