Contributed by alert reader Dan LaLiberte. Details are sketchy.

Apparently there is an episode in which Samantha (our hero) is trying to help out her neighbor Gladys Kravitz with her (Gladys's) witching skills. She writes a number (not 37) on a piece of paper and tells Gladys to guess what the number is. Gladys guesses 37 (good for her!). Samantha does her little nose-twinkle thing, and the number on the paper changes to 37. Congratulations Gladys, you (ahem) got it right!