On the SitePoint PHP blog there's a new tutorial posted by Wern Ancheta showing you how to offer "calendar as a service" in your application with the help of the Google Calendar API. The Calendar API provides access to all of the features you'd expect from the Google Calendar system and the tutorial helps you make a fully functional overlay integrated with it and living in your application.

In this article, you’ll learn how to work with the Google Calendar API in PHP. You’ll do it by building a calendar app that allows users to add new calendars, add events, and sync calendars to Google Calendar.

The tutorial then walks you through every step of the process you'll need to get your application hooked into the API and the code to use for the integration:

• Setting up a Google Console Project
• Building the App
• Configuring the App
• Creating a Service Container for the Google Client
• (Adding) Routes
• Admin Route Middleware
• Database setup
• Home Pages creation
• Admin Pages creation
• Creating a Calendar
• Creating an Event
• Syncing a Calendar
• Listing Events
• Logging Out

The application they create is Laravel based and makes use of a bit of Javascript in the views for the date selector and handlebars templating.