This is the first time I've actually gotten my hands on Google Cardboard! (surprising, I know)
While I've had trouble figuring out the potential use case for this in the past, it just seems like so much fun, I'm sure we'll find something useful to do with it, and I can't wait to check out the OnePlus Two launch event!
Link for more info (sold out, potentially forever?): https://oneplus.net/cardboard
LOTS of Google Cardboard alternatives available, though: http://amzn.to/1GjR0qP