The Running Gag of Clementine only calling her brother by vegetable names, such that readers never even learn his real name and in one installment she actually goes to a Chinese grocery store in order to find new ones.
From Clementine and the Family Meeting:
When I went over to the refrigerator to get the milk out, I saw our FAMILY MEETING! sign again. ... My mom took the jug from me and sniffed it, and then nodded at it with her Good-job! smile, as if she was proud of our milk for not turning sour.
Additionally from Clementine and the Family Meeting, Clementine having her little brother sit on their father's snow shovel and the father reacting with amusement about how heavy the shovel is, while pretending he doesn't know that his son is on the shovel. Doubles as heartwarming when Clementine isn't sure at first whether or not to feel upset about the fact that she's too big to pull this gag with her father anymore, then knows exactly how to feel when her father gives her a big wink.
In the original Clementine book, Clementine telling her mother that she can't go to school because she has the "heartbreak of sore irises."
