Countdown to insert in PPT
 

This post seems most appropriate for Patrick, but I'll ask everyone:
Does anyone know about an easy way to insert a countdown clock in a powerpoint or a PPT template with one? I am designing a series of 'Password' games to go with my textbook and have made a very homemade thing by using the animations in PPT. I was dreaming of a clock that would ring in a minute or so, but what I found in the web was either full page or flash or too complicated to insert. Any help out there?