Very simple calendar?

Is there a very simple calendar that just alows a manager or site admin just to easily highlight a number of dates and have them shown on a calendar that is visiable but not editable to vistors?

I do not need the ability to link it to modx documents of anything like that.

Thanks

do you mean something like that:http://www.webcmsolutions.de/index.php?id=14

hightlight/unhighlight with one mouseclick. (Goes directly to the database if one has permissions to do that).
its another example done with xett.