Rainlendar supports events and tasks which both are kept in separate lists. This helps you to keep your life better organized and makes it easier to see what are the upcoming things you need to do.
Rainlendar - The Flexible Calendar App

Get notified in advanced before the event is due so that you don't forget your important events. It is also possible to snooze the alarm if you want to get reminded about it later.

Rainlendar is a customizable calendar application which stays out of your way but keeps all your important events and tasks always visible on your desktop.

The look and feel of the calendar can be changed with skins. The application works in all major operating systems: Windows, Mac OS X and Linux.

A useful Idea with Rainlendar....from SAN Gear

Please do not do this on Low RAM systems, at least 1 GB.

I wanted a desktop, always on corkboard or whiteboard; still no solution that fits me.

My needs are free, low ram, low cpu. No way!

At least a compromise for now, I used rainlendar single month view only. Transparent and click through. Large to fill the desktop nearly. That it the best part of this tool, highly Tweakable.

Now i have a Wallpaper Calendar on which i can write my memos. I press shift and click any day. make a To-Do or event. You can make both show using settings. Then it becomes transparent and un-clickable. The desktop shows my month memos.

Thank you Rainy, i am playing with this calendar again after many years. Your calender better than before. It is a Client for Webapps too. 

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