The best resource for learning Google Script is the official documentation available at developers.google.com. Here are other places that will help you get up to speed.
- Case Studies - Sample Google Script Projects (google.com)
- Google Apps Scripts - Snippets by +Amit Agarwal
- scoop.it/t/gas by +Martin Hawksey
- Awesome Google Scripts by +Amit Agarwal
- O'Reilly - Apps Script - by +James Ferreira
- Apps Script Webinars - YouTube - by +Eric Koleda and +Arun Nagarajan