It allows the user to browse and play music and video files, browse pictures and play photo slideshows, retrieve information about media files from the Internet (such as covers, fan art, song lyrics, and much more) and build an indexed database of available media.
A press release and screenshots are available. Enna can be downloaded in source format; prebuilt packages for Ubuntu 9.10 Karmic are also available. Enna will be the user interface of the upcoming GeeXboX 2.0 media center Linux distribution.
Over the past few years, I've become an avid user and tester of various media centre interfaces, and while I think Windows Media Center receives the polish award, the various XBMC variants (and XBMC itself, of course) definitely deserve the feature and flexibility awards.
I did a quick test of Enna on Ubuntu 9.10, and it indeed looks very good, and barely consumes any system resources. It's still quite limited in configuration, obviously, as it's all so new, so it won't draw me away from Boxee for the foreseeable future. It is a very interesting project though, if only because it uses the EFL.
Definitely one to watch, and it's easy to give it a shot on Ubuntu.