Wallpaper Clocks  can be used to display “live” wallpapers for your Ubuntu box. By “live” I mean that these wallpapers have real-time working clock blended into the wallpaper image. There are ton’s of these wallpapers available at the website linked above,which really brighten up your desktop, most of these wallpapers are free to download. Now the application to get these wallpapers working with the embedded clock / calender for Windows and other platforms are not free. But for Ubuntu it sure is. All you need to install is the Screenlets .Which has an app that does this job.
sudo add-apt-repository ppa:screenlets/ppasudo apt-get updatesudo apt-get install screenlets
The Screenlets PPA comes with a huge list of screenlets by default such as: Google Calendar screenlet, Gmail screenlet, Folderview screenlet, Ring Sensors, Terminal, Twitter, Notes, the amazing WallpaperClock Screenlet  and many others. You can use some of these for more eyecandy. After the installation, run Screenlets from Applications > Accesories > Screenlets and you would see the Screenlets Manger like the one shown below. You can select any applet and then choose to start it, you can also tick the box to enable auto loading of that particular Screenlet.
If you want still more Screenlets, you can choose to install them all
sudo apt-get install screenlets-pack-all
Now, lets get back to our main focus. Launch Wallpaper clock using Screenlets Manager
Now you would see a small clock like icon on your desktop, right click to configure it or to install new Wallpaper Clocks which you can download from Wallpaper Clocks Website .
Have fun with Wallpaper Clock.