To all who were involved into this theme in any way: Thank you! I tried to find out who's theme it is, but it turned out that way too many people were varied it and worked on it.
So please be indulgent when I do not mention your name here!!!
This is a variant of the aeroclock (http://www.kde-look.org/content/show.php/aeroclock?content=37182).
I was up to something else than a silver analog clock on my desktop, so I modified it to fit with the black dbKalendar theme.
I'll do some more work on it, but it's ready to use.
Have fun with this! :-)
UPDATE: If you vote bad, please leave a comment! Thank you.