Android/iOS: Earlier this year, Google announced a couple of new messaging apps (like it does every year, it seems). One of them is a one-to-one video chat app called Duo. Now, it's finally rolling out to users. Google pitches the app as the most dead simple video calling around. All you need to make a call to someone is a phone number. It seems to be aimed at competing with Facetime, with the added benefit of working across both iOS and Android. The app is currently rolling out over the next few days. If it's not available for you from the source links below, sit tight and wait out the week.