Loxi - Easily add an events calendar to any website.
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Whenever - Casual calendar app for iOS
ioBroker - flexible and modular application for the IoT and Smarthome
Future - Calendar events around the clock
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation