(There were a bunch of parents at school today for a basketball game, and evidently I looked like one of them.)
Student 1: "Mrs. Strassner... wow, you looked like a mom from the back."
Student 2: "Really? I thought she looked like a mom from the front!"
(While both of us were turned sideways in front of the mirror.)
Me: Observing the remarkable difference in our sizes.
Casey: "I'm like the Kansas to your Colorado!"
(Eating goldfish crackers during class; kind of a no-no.)
Student: "Why do you get to eat during class?"
Me: "When you can do this" (pointing to belly) "you can eat during class too!"
(Disclaimer: it was a male student, which makes the story much less inappropriate. I really would never have said that to a female student!)