The best resource for learning Google Script is the official documentation available at developers.google.com. Here are other video tutorials and online learning resources where you can get up to speed using Google Apps Script that will let you programmatically access various Google Apps and services include Gmail, Google Drive, Calendar, Google Forms, Google Docs and more.

Also see: How to Learn Programming Online

1. Most Useful Google Scripts
2. Google Scripts for Developers - a collection on Google+
3. Google Script Projects Case Studies on google.com
4. Google Apps Script - Code Samples
5. scoop.it/t/gas by Martin Hawksey
6. GAS for Developers - Video training by Bruce McPherson.
7. Apps Script Webinars - YouTube - by +Eric Koleda
8. StackOverflow Q&A - Got a question? Ask here.9. lynda.com - Scott Simpson (Up and Running with Google Scripts)
9. Tutorial - Written Google Docs Addons
10. Known Issues & Bugs - Report a bug here.