PlexyDesk is an open source desktop extension for Windows, Mac and Linux based operating systems which transforms the look of the desktop and allows adding QML based widgets. It is not to be mistaken for a desktop environment like KDE or Gnome. Instead, it renders the desktop workspace and allows you to organize it. Currently, it provides a clock widget, photo frame, and file browser on the main sand allows adding extra widgets via drag and drop, which can further change the look and feel of your desktop.
To install PlexyDesk in Ubuntu 11.04, enter the following PPA in Software Sources and head over to the Ubuntu Software Center to install it.
Once installed, launch PlexyDesk from the Unity Dash. It sits in the system tray and instantly changes the look of your desktop (as long as it is active). You can drag and drop the clock, picture frame and getting started guide widget anywhere on the desktop to suit your needs. Whereas, the compact file browser provides the convenience of managing your files and folders within a small auto aligning file browser. Extra QML based widgets can also be added by simply dragging them onto the desktop.
Similarly, you can drag and drop images on to the desktop to set them as the background wallpaper or the picture frame. The Getting Started Guide provides information about adding and removing desktop widgets and the background wallpaper, along with a link to the Wiki page of PlexyDesk.
Unfortunately, there is currently no easy way of installing PlexyDesk on Windows and you will require compiling the source package for which you can find instructions here. Having said that, PlexyDesk is currently under heavy development and it is likely that more features will be added soon. You can suggest features to the developer and download PlexyDesk package for your operating system version from the developers website. PlexyDesk works on Windows, Mac OS X, Ubuntu Linux and Meego.