The Elementary OS crew, a group of young designers seeking to create a beautiful and simple Linux distribution, have released Elementary OS 0.2 "Luna" as their latest Ubuntu-based operating system.
Elementary OS Luna has a basic desktop layout, a simple file manager, and relies upon Midori as its web-browser.
For more details on the release of Elementary OS Luna is a lengthy post
about what went into the release, etc. There really aren't as many technical innovations in the distribution as they are just seeking about beautifying the end-user interfaces.