Ah yes I well recall this great "Beat the Time" skit with Grover. (I liked the Cookie Monster one even better). It was five things actually that Grover had to find that contained milk. And he finds cheese, butter, and ice cream and then just before the buzzer sounds he brings in 2 cows to make a total of five! And Guy Smiley shouts, "Wonderful!" and music plays and Grover is a winner. Shortly after I saw this skit in the early 70's I got a joke book that had classic jokes like "Why did the boy throw the clock out the window? He wanted to see time fly" and "What time is it when an elephant sits on your fence? Time to get a new fence". Well, one of the jokes was, "Can you name five things that contain milk?" And the answer was, "Cheese, ice cream, butter, and two cows." So maybe the joke preceded the SS skit. As a first grader I would enjoy expanding this joke by saying, "I can name a hundred things that contain milk." Then when a kid would say, "No way", I would say "A hundred cows!"