For all those times when adding a quick reminder to iCal is too cumbersome, or you might not be online so the Backpack widget
can do its thing, the Reminder widget might be right up your alley. As you can see, the widget has a simple interface allowing you to add some type of a reminder name/message, along with a reminder time. As an added bonus, this widget actually adds events to its own iCal calendar.
The Reminder widget is, of course, free and available from DashboardWidgets.com