A blonde is in a store and sees a thermos. She picks it up and asks the clerk what it is. The clerk says, "It's a thermos. It keeps hot things hot and cold things cold."
The blonde decides to buy the thermos. She brings it to work the next day. The blonde's boss (also a blonde) asks what it is. "It's a thermos. It keeps hot things hot and cold things cold," explains the blonde. "So what do you have in it?" asks the boss. The blonde answers, "Some hot chocolate and a popcicle."