Etoile (
http://etoileos.com/ ) is a desktop and a set of libraries based on GNUstep (GNUStep is already packaged in Ubuntu). The idea is that different tasks are handled by different Services, with interfaces allowing them to interact and build complete applications. Think of Etoile being to GNUstep what OSX is to NEXTstep, a bit.
As a desktop it is nice to play with, and would be comfortable for people switching from Mac. The applications built for Etoile and GNUstep cover the basics, like IM, email, news, text editors, file managers, etc. but there are a lot of gaps which would benefit from more exposure and more developers.
The development being done is very cool, with recent activity such as a Just In Time compiler for Smalltalk (based on LLVM), allowing application development in Smalltalk with transparent access to all of Etoile's Objective C components (rather than being stuck in a Smalltalk-only world like Squeak).
At the moment there is an Ubuntu-based live CD of Etoile (here are some screenshots
http://news.softpedia.com/news/Etoile-Live-CD-48502.shtml ). However this contains an old prerelease version of Etoile 0.2 from February 2007 (as far as I can tell). It includes a complete Etoile desktop on top of GNUstep on top of Ubuntu.
Ubuntu currently has a source package for etoile, but it only builds into Camaelon (a theming tool) DictionaryReader and WildMenus (which is a dummy package).
Getting an up-to-date version of the whole Etoile system means checking it all out of subversion and compiling. The etoile developers are not making packages for any systems at the moment, but they say they would be happy to help packagers with any problems they encounter.
The issue being raised in this rationale is that the innovative Etoile system and desktop, while packaged, are not being made available to users other than two applications mentioned above.