Countdown 99

From Contact Plus Corporation:

Takes up to 25 dates in the past or future and calculates the number of years, months, days, hours, minutes, and seconds. Also the total number of hours, minutes, seconds and weekends are displayed. The screen is refreshed each second so you can get an interesting look at elapsed time. You can tell exactly how many weekends there are since the year 2000, how many seconds you have been alive, or how many days until your anniversary. Used by members of the US Military stationed around the world to tell when they are going home, anniversaries, birthdays, etc!