How did I just do that? I'm using Windows Hello, a new feature of Windows 10 that logs you in with your face instead of a password.
It gets better: Microsoft plans to let you log into all kinds of things the exact same way. Once your computer knows that it's actually you sitting in front of your laptop or desktop PC -- the idea goes -- supported websites, social networks, and perhaps even banks will let you log in with your face instead of a password, too. It's all part of an initative called the FIDO Alliance, of which Microsoft is just one member.
But don't go looking for the same option on your freshly upgraded personal computer. In order to ensure that it's actually you at the controls, Windows Hello requires a pretty fancy camera: one equipped with an infrared depth sensor so it can see your face in three dimensions. Just like a Microsoft Kinect.
That way, people can't fool the system by just holding up a picture of your face, or something.
There aren't a lot of cameras like that on the market right now. Pretty much just devices with Intel RealSense cameras work with Windows 10 at the moment, and that's what you see me using in these animated GIFs. I've got an Intel RealSense developer kit that was an absolute pain to install and has some really shitty driver issues... but as you can see, it works brilliantly. Just a glance and I'm logged in. In fact, if I power up the computer while sitting in front of it, I'll seamlessly toss me into my desktop.
There are some other biometric scanners that work with Windows Hello, too, including a number of fingerprint sensors and even iris scanners. And failing those, you can just create a four-digit PIN. But the camera's definitely the coolest, most seamless way to go, and I've honestly got no clue if laptop manufacturers are going to buy in, because the camera's not really good for much else yet.
Here's a list of all the devices you can get with an Intel RealSense camera so far.