I got the name of the movie wrong it was actually called Cold Turkey (1971) and Dick Van Dyke & Pippa Scot starred in it. Here is the plot "Plot Synopsis: Reverend Brooks leads the town in a contest to stop smoking for a month, But some tobacco executives don't want them to win, and try everything they can to make them smoke. If townspeople don't go nuts, from wanting a cigarette, or kill each other from irritation and frustration, they will will a huge prize. "
What keeps me smiling is what the character Dick Van Dyke plays does when he craves a smoke (cig). What gets me laughing is the expression on his wife's face when she sees him walking up the sidewalk.