Per the title, Simon Says is a children's game for three or more players where one is "it" and tells the others what to do when asked with a phrase beginning with "Simon says".
This is the fifth of ten appearances Sammy Smith makes in the series, most of the time appearing as the malt shop waiter. His appearance is uncredited in this episode.
This is the fifth of 12 appearances Kitty Sullivan makes in the series as Sue Ellen. The character appears first in The Tycoons (1964), but is played by Susan Tyrrell.