"OpenSolaris is the state of the art, cutting edge operating system that provides a rich, coherent platform for building and running applications.

OpenSolaris offers free, built-in features that help you build, debug and deploy new applications faster. It's is an operating system (OS), an open source project licensed under CDDL, and a community.

The project's goals are innovation, collaboration, and the extension of OpenSolaris technology." (www.opensolaris.com)

They just released the 2008.11 version, with some new cool tools like TimeSlider and much more hardware compatibility.

You can download it here: http://www.opensolaris.com/get/index.js

You can see a walk-through the installation here: http://blogs.sun.com/amitsaha/entry/open_solaris_2008_11_on

You can see videos and talks about the release and the new stuff here: http://www.opensolaris.com/learn/

You can get in touch with the community here: http://www.opensolaris.org

You can see the hardware compatibility list here: http://www.sun.com/bigadmin/hcl/

Download it! Try it! Enjoy it!