DesktopCalendar 1.0   
by fCoder Group International   

In the real world you always place the calendar in some easily accessible place, to be able to see it at any moment, so, why should you run some extra program to do the same thing on your computer? This is the basic idea that lies behind the creation of Desktop Calendar. We think that desktop is the most appropriate place for a calendar and Desktop Calendar utilizes your existing wallpaper for this purpose.
When you first start the program, it adds calendar for the current month to your wallpaper image. That is all! You don't need to bother about anything at all anymore. The program will sit in the system tray and refresh the image when necessary highlighting the current date (if you want to make some changes, double-click on the icon to bring up the settings window). It takes very little system resources and will not degrade your machine performance.
Perhaps you will need to rearrange some icons, so they wouldn't obscure the calendar items, but you can always adjust size, position and look of the calendar to avoid making big changes.