Remix OS for PC is a lightweight fork of Android KitKat, optimised for desktop use, which you can run from a USB stick or virtual machine.
While that sounds interesting, there are catches. It's an alpha, officially flagged as a "developer" edition, so problems are to be expected. And there's no Play Store included, which means it takes a little more work than usual to install your favourite apps.
If you're happy to try it anyway, the download gets you an ISO image. Burn it to disc, make a bootable USB stick or plug it into VirtualBox and you should be able to boot from it on most PCs.
There's the usual LiveCD procedure: choose Guest Mode, select your keyboard type (there's only US and Chinese, unfortunately), click Next to agree to the licence and click Start. (If you're using VirtualBox and it hangs after you select Guest Mode, make sure you've created your virtual machine based on 64-bit Linux.)
Remix OS opens with a very Windows-like desktop. There are icons on the desktop, a Start Menu when you click bottom left, a Windows 10-style notifications panel if you click bottom right.
App windows are designed with the mouse in mind. Move your mouse to the bottom right corner of a window, the cursor changes and you can click and drag to resize it, while the title bar has PC-like minimise, maximise and close buttons.
The File Manager will also seem familiar to Windows users, its left-hand panel of common locations (Documents, Pictures, Music, Desktop, more) taking them wherever they need to go.
Basic usage is much like a PC, too. Double-click to launch things, buttons appear on the taskbar, click or use Alt+Tab to switch between them, or right-click for more options.