Google Chrome OS

Google Chrome OS is a Linux-based operating system designed by Google to work exclusively with web applications. Google announced the operating system on July 7, 2009 and made it an open source project, called Chromium OS, that November. 
Unlike Chromium OS, which can be compiled from the downloaded source code, Chrome OS will only ship on specific hardware from Google's manufacturing partners  The user interface takes a minimalist approach, resembling that of the Chrome web browser. Because Google Chrome OS is aimed at users who spend most of their computer time on the Internet, the only application on the device will be a browser incorporating a media player. 
The expected launch date for retail hardware featuring Chrome OS has slipped since Google first announced the operating system: from late 2010 to early 2011 to, by some reports, mid-2011. 
 ^{source::wikipedia}

Google Chrome OS, running on a Google Cr-48 Notebook, from the December 2010 pilot program.
Company / developer	Google Inc.
Programmed in	C, C++
OS family	Unix-like
Working state	Source code released as Chromium OS
Latest stable release	0.11.257.44 (Beta) / April 14, 2011; 2 days ago (2011-04-14)
Latest unstable release	0.12.397.0 (Dev) / April 14, 2011; 2 days ago (2011-04-14)
Supported platforms	x86, ARM
Kernel type	Monolithic (Linux)
Default user interface	Graphical interface based on the Google Chrome Browser
License	GNU General Public License and BSD license (for Chromium OS — Chrome OS has not yet been released)
Official website	google.com/chromeos/