https://arvr.google.com/cardboard/
We got one years ago when they first came out. Fun toy, but it's been sitting in a drawer for years now. But I guess as the VR on the phone gets better, I should try it again.
PS - I just checked. It came out in 2014. I think we got ours right about then. Around then, some famous tech journalist Robert Scoble(?) keynoted at Pubcon and was saying that VR was coming fast.