The ROX Desktop has forked a couple of the GNOME Core Applications and written some from scratch. Most applications developed by the ROX Desktop team are forks of existing GNOME applications and based on GTK+ and Clutter.
The ROX Desktop is a desktop environment based on the ROX-Filer file manager. Files are loaded by dragging them to an application from the filer, and saved by dragging back to the filer. Applications are executable directories, and are thus also installed (copied), uninstalled (deleted), and run through the filer interface. ROX has a strong link with Zero Install, a method of identifying and executing programs via a URL, to make software installation completely automatic.