Amos

Primer - The CSS toolkit and guidelines that power GitHub.
http://primercss.io/

kanru

Ledger is a powerful, double-entry accounting system that is accessed from the UNIX command-line.
http://www.ledger-cli.org/

Parse - Build powerful mobile apps faster with user management, push notifications, storage and analytics powered by Parse.
https://parse.com/

$ git format-patch —cover-letter

Mattermost - an open source, self-hosted Slack-alternative
http://www.mattermost.org/