 There is still some debate over the meaning of the title. When the  show was first shown by ATV it was known simply as "Today is  Saturday", and this became expanded to "TISWAS" when it was  televised nationally. Although "Today Is Saturday Watch and Smile"  is often suggested (and is referred to as such in a recent  Chris Tarrant (qv) biography) most fans and assorted websites tend  to favor "Today is Saturday Wear a Smile". To date the question  remains unanswered.