I just reinstalled my Ubuntu (I've 12.04), installed Gnome 3, and I want my login screen look like this (I've had it before but I really don't remember how I did it). I tried to search for "gnome login screen" but nothing useful showed up.
This is the login screen I want:
This it the login screen I have now:
Any idea how to get it? At least what is the name of this "theme" ?