Using Ubuntu,

I tried to several desktop environments. I tried Unity, Gnome, kDE (?) and now Cinnamon. I liked Cinnamon, I once saw screenshot of someone who has nicely modified it, to make it look very awesome. He had clock in top right corner which seemed on be on background level, he also had darkened menu background and the bottom bar to really dark, so I think it looked very awesome. I tried to Google "How to modify looks of desktop environment?", which provided me with list of most popular desktop environments. "How to modify appearance of desktop environment?", produced same result. How can I modify color and background of objects? I know you can change font colors, family type and sizes, but that's not background. Also, how do I download such cool widgets like clock?

Take a look at this. Should tell you all you need to know know:
http://cinnamon.linuxmint.com/?p=144

As for the clock, I have no idea. Could it be conky, with a custom theme? Can you post a link to the image you saw it in? Might yield more clues!

Deleted by self.

I can't find the actual picture of which I saw, sorry. I'll keep looking and I'll post here as I find it.

But where do I find such addons at all?

@edit 2 - Can't find it :(.