Google OS
Chrome OS
http://www.chromium.org/chromium-os
Try Chrome OS in VirtualBox Before Buying a Chromebook
Google’s Chrome OS is built on the Linux kernel, but it replaces the desktop and user-level software with a specialized desktop that can only run the Chrome browser and Chrome apps.
Chrome OS isn’t really a general-purpose PC operating system — instead, it’s designed to be preinstalled on specialized laptops, known as Chromebooks. However, there are ways to install Chrome OS on your own PC.
Android
Run Android on Your PC and Make Your Own “Dual OS” System
Android also uses the Linux kernel, but practically everything else on Android is very different from typical Linux distributions. Originally designed for smartphones, you can now get Android laptops and even desktops. It’s no surprised that a variety of projects exist to run Android on traditional PCs — Intel even develops their own port of Android to PC hardware. It’s not an ideal operating system for your PC — it still doesn’t allow you to use multiple apps at the same time — but you could install it if you really wanted