Rupert Breheny, a Google Webmaster - yes, Google has their own webmasters responsible for building out both front facing web sites (such as Google Play, Picasa, Google search and more), participated in Webmaster Hangout on Google+ with Google's John Mueller.
He gave a great presentation, aimed at folks fairly new to responsive design, on best practices and stories he had with making Google's own web sites responsive. It is definitely worth listening to when you have an hour.
Rupert Breheny works out of the Zurich office, he worked on the Picasa home page and specializes in HTML5, CSS3, JavaScript, Accessibility, Validation, and Responsive Design. You can follow him on Google+ if you want.
Here is the video of the hangout:
I don't think there are any hidden ranking gems here but good responsive design presentation.
Forum discussion at Google+.
