Cinnamon: GNOME Shell Fork With A GNOME2-Like Layout
Clement Lefebvre, the Linux Mint founder, has started working on a GNOME Shell fork called Cinnamon, which tries to offer a layout similar to GNOME 2, with emphasis on "making users feel at home and providing them with an easy to use and comfortable desktop experience":
Cinnamon is a Linux desktop which provides advanced innovative features and a traditional user experience. The desktop layout is similar to Gnome 2. The underlying technology is forked from Gnome Shell.
Why For GNOME Shell?
Why fork GNOME Shell? According to Clement Lefebvre (who talked about this on IRC @ #mate), the reason is that even though extensions are cool, you can only do a small amount of stuff with them and you can't control interactions between extensions, their loading order and so on.