Have you heard of the Oculus Rift? It's a new "virtual reality" peripheral for gaming, and the latest way to look like a big ol' idiot while sitting on your couch! Kidding aside, the possibilities the Oculus Rift present are amazing, especially considering all the opportunities you'll have to do this to your friends.
There's nothing unsafe about completely shielding your vision when playing video games. Totally won't open yourself up to being punched in the stomach or anything like that. Nope, just good times.