At the time of writing (December 2002), the programme is broadcast from 16:15 to 17:00 every weekday, with each programme repeated in the early hours of the morning about two and a half days later.
Countdown is based on the French game show Des Chiffres et Des Lettres (Digits and Letters). It was originally broadcast in the Yorkshire Television ITV region as Calendar Countdown - Calendar being that region's local news magazine show which was, at the time, fronted by Whiteley. Yorkshire Television, now part of the Granada Television group, still makes Countdown for Channel Four.
The main task set for the two contestants is to make the longest possible word using nine not-quite-randomly selected letters of the alphabet, in a time limit of thirty seconds. The word-making rounds are interspersed with rounds in which the contestants are asked to use a set of not-quite-randomly selected numbers to make a sum that gives the total generated by the resident computer. Finally, the "Countdown Conundrum" is a one-word anagram, to be solved by the quicker of the two contestants. Further entertainment comes from a celebrity guest who assists the "guardian of the dictionary".
Countdown, like most of the "old guard" of British game shows is never so much about winning prizes as simply competing (and possibly showing off to the nation how smart you are). The current prize fund tends to be a board game and other assorted items for every contestant and a full Oxford English Dictionary for the series winner, which is still a lot more than it used to be.