How many clocks you have on your desktop?
By default Windows have a single clock at the right section of the taskbar. In Windows 7 we can also get this option. Also we can go beyond of that. In Windows 7 we can set up at most three clocks. One is the default and two additional clocks. The three different clocks can show date and time on three different time zones. The idea is we can use the main clock as our primary date and time zone, for example our current location. Additional two clocks are for our additional usage, that means our secondary usage. If we need more clocks then we have to go for other solution. Windows 7 has desktop gadgets. In gadgets there is a clock gadget which we can use to show a clock on our desktop. We can add as many clocks as we need on our desktop. But it has difference with the system clocks (which is at the right side of the taskbar). System clocks can show you time with AM/PM and day of the week. But clock gadgets is only for time.
I use three clocks at system clocks. First one is for my main time zone IST, second one is for UTC and third one is for ET. UTC (Universal Time Coordinated) is because it is the universal time of the world. ET (Eastern Time of US and Canada) is one of the important time zone in the world. I need that date and time in many situation. Apart from these three clocks if I need more then I go for the clock gadget. For example currently I have a client who is in Japan, so I some times need to know the Japan’s current time. On my desktop there are two clock gadgets. One for the regular one (IST) and another for the Japan’s time. This is the clock settings which I currently using.