The New York Times distributed over a million Cardboard VR sets this weekend to their newspaper subscribers. They also produced an original VR documentary, watchable on your phones (via Cardboard).
This strikes me as a genius marketing move by both companies.
Update (11/23): I got a Cardboard and watched the documentaries on this NYT page. It was uncomfortable to hold the set to my face and I had to pause a few times due to disorientation. Definitely some kinks to be ironed out, but I'm excited to see the technology and content evolve.