Google Assistant switches Sonoff S20 Switch your light on/off using your voice and the help of Google Assistant. Sure, you can run to the store and purchase a preconfigured light switch, but what's the fun in that and more importantly these switches with their close-source software require access to your home network.
Talk to your CD player using Google Home Describes how to use a microcontroller and infrared LED, to let Google Assistant control infrared enabled devices.
Arduino parts Overview of parts and tools that I use to build Arduino projects. Includes breakout boards, shields and development environments.
ESP8266 based alarm that synchronizes with Google Calendar ESP8266 based alarm clock that fetches you AM appointment from Google Calendar and sets an alarm accordingly. Uses a Google Web App script.
ESP8266 reads Google Calendar This is not exactly the first approach of pulling data from Google Calendar, but it may be the first that directly connects to Google. This program calls the Google Script API, that in returns the relevant calendar event.
Pitch Detection on Arduino using Autocorrelation A device that recognizes the notes played on a musical instrument. 1st place in the Silicon Valley science competition. 
Arduino Infrared Interface for SilverLit RC Vehicles Control your Arduino creation using the remote control that came with the SilverLit RC dump truck, flatbed, bulldozer or crane. This article describes the protocol and its implementation for Arduino.
Web browser accessing Arduino data This article shows how an external web site can change i/o values on your Arduino. All you need is a RGB LED and an Arduino with an Ethershield or the newer Arduino Ethernet.
Snapshot Backup with the DNS-321 NAS using rsync Describes how to make daily and weekly backups using rsync, while preventing file duplication between the different backups.
Secure Internet Appliance for home office How to build a Firewall, VPN Server and Wireless Access Point on a single board computer using open source software components.