Google Chrome OS open sourced as Chromium OS

Google Chrome OS is now open sourced as “Chromium OS”. This means code is free, accessible to anyone and open for contributions. Chromium OS project includes current code base, user interface experiments and some initial designs for ongoing development,” Google.

• It's all about web. All apps are web apps. Entire experience takes place within browser and there’re no conventional desktop app, means users don’t have to deal with installing, managing and updating programs.
• Second, because all apps live within browser, there’re significant benefits to security. Chrome OS doesn't trust apps you run. Each app’s contained within a security sandbox making it harder for malware and viruses to infect your computer. Chrome OS Security Overview.
• Chrome OS is a lightweight Linux distribution based on Debian that uses a lot of open-source software: Host AP Linux drivers, PAM (an authentication mechanism), Syslinux (a lightweight bootloader), IBus (Intelligent Input Bus for Linux / Unix OS), ConnMan (Internet connection manager), XScreenSaver and other software.
• Google Chrome OS will be ready for consumers this time next year. Sign up here for updates or if you like building your operating system from source

If you're willing to take the plunge you can download here, an engineer over at Gdgt.com has compiled source code and directions to install OS.