makeuseof.com says :

"Just a few days ago, Google announced the release of the Chrome OS source code. Within less than 24 hours, the web was littered with disk images for running the new OS on virtual machines such as VMWare and VirtualBox. I even managed to put together my own Google Chrome OS download in the form of a complete VirtualBox appliance. I’m pleased to announce that I’ve taken it a step further, and now you can easily try it on your own computer from a USB thumb drive."

detail is here http://www.makeuseof.com/tag/download-google-chrome-os-and-run-on-a-real-computer