Rainlendar Lite is a small and compact desktop calendar that comes with some powerful features under the hood. It integrates nicely with your desktop wallpaper and allows interactive access to selected dates, just click on a date to add an appointment or reminder.
Rainlendar also comes with a ToDo list that can optionally be displayed or maintained hidden. The calendar automatically supports one-time and recurring events and tasks with optional reminder alarms. It highlights dates that have appointments and you can quickly switch between months via keyboard shortcuts or your mouse wheel.
A Pro version is available that can synchronize with Outlook.
I just wanted to say that Rainlendar has been constantly improving their Calendar program to allow customized event, tasks (To-Dos), alarms, and views. It is unique in the way it does things but it well worth it. Out of the box it works, easy to configure and use. The look and feel is wonderful with the transparency overlay on the desktop. The cpu and memory usage are minimal while running in the background. Have fun customizing our own calendar!