Rainlendar is a calendar that is displayed on the desktop, and it allows you to carry to-do lists, reminders, alarms, such as birthdays, dates to do paperwork, payment due dates, and so on.
The calendar always stays on the desktop, floating over the icons as it is transparent. There are several designs and skins to choose from, and you can regulate the level of transparency.
When an event is entered, the date or period in which the event is displayed is entered, and an alarm can be added to alert you for a few minutes (or hours, days, etc.) before,
In addition to serving to remember events or annotate tasks, also functions as a simple calendar in which dates can be consulted, similar to the one that comes with Windows.
It has some advanced functions that can be added by scripts, and also has a tool that allows to synchronize with the cell phone all the information stored in the calendar.
Rainlendar 2.11.1 Lite is the latest version (updated January 2013) of this useful software, which can be downloaded for free. It is available in Spanish and works with all versions of Windows, in addition to Linux and Mac.