So, Google's new Hangouts app
You can now show two angles of yourself at the same time. Turn your head from one to the quickly for instant comedy. But why stop there? I pulled out my tablet, and yep, that worked, too. In the image above you can see there's three of me and two of him.
This may not have been an intentional Easter egg, but it's fun nonetheless. There might actually be a modicum of utility, even. You could continue to show your face, while you use the camera on your phone to show some project that you're working on. Or maybe it's so you can switch from one device to the other without having to hang up. Really, though, you're just going to use it to weird people out, and that's just fine. But watch out for audio feedback. It can be harsh.