Google Chrome extensions have become a hot topic in our district...mainly because we have had some students using certain extensions to try and get around our servers :). We shut off access to the google web store for students but we are promoting the use for teachers.
Quite possibly my favorite extension is the the URL Shortener. The extension becomes added to your Google Chrome task bar and when you click it you can immediately get a shortened URL and a QR code. It is quick and easy and makes making a QR code for a specific site so much easier.
The two pictures above show what it looks like on your task bar (picture #1) and how to install it (picture #2).