One of the first dynamic pages I wrote for my web site was a countdown calendar. The idea is simple. You choose a date on a calendar:
Once you choose a date, you are shown a new calendar that shows every date between today and that date, along with the number of days left until then.
So if you're anticipating a big date, e.g. a graduation, a wedding, retirement, or when the moon blasts out of earth orbit, try my countdown calendar.