the clock at the top of desktop is one of screenlets
if you want this widget like Windows 7 widget.. add components from screenlets manager..
to activate this application..please.. follow steps bellow..
#step 1
as usual.. update repository
sudo apt-get update
sudo apt-get update
#step 2
install application
sudo apt-get install screenlets
#step 3
config as you want.. finish.. :)sudo apt-get install screenlets
#step 3




