The new University of Notre Dame website is already a classic. The responsive approach and superb details make this worth every second of your scrutiny and study. I found this via this great interview about nd.edu here.
I really like this answer to why the team chose to go the responsive route:
What inspired you to take this approach for ND.edu?
At Notre Dame, we have a long history of trying to make things accessible. Mobile and responsive sites are a part of that tradition—it’s a way of making web content more accessible to more people.