How To Implement Google Calendar
Into Your Website
Seems like a simple request: Display events from Google calendar on a website.  It also seems like good skill for a web developer that can add value for customers.  But I spent quite a bit of time hacking my way to these objectives.  And if anyone else is motivated to undertake this effort, perhaps my experience can help.
Google uses REST and OAuth2. The good thing about REST is that examples can be presented as a single curl command.  But Google is quite fussy about implementation details, and doesn't provide many examples.  Google's examples all rely on their libraries and only a handful of languages.  So it's hard to distill the actual REST queries.  The examples below are written in curl.  Curl is universal and anything unfamiliar has a straightforward explanation on the curl man page.
Most of the difficulty seems to lie in the OAuth2 implementation.  Perhaps a solid understanding would have made my experience easier.  Provided Google adheres to the standard, this explanation probably illuminates that protocol as well.