Irish comedians used to get good mileage out of this one. It's in the 'Whose on first" genre:
A father cobbler is introducing his rather simple son to shoemaking.
Dad: Now, Son, the first thing you get is the last. son: How can the first thing you get be the last? Dad: The last is what you get first. Son: So what do you get last? dad: that's First! Son: So what is? dad: Your Grandfather's old Iron Foot. son: I didn't know he was disabled. Dad: No, Granddad's old Iron Foot is the last. son: Which comes First? Dad: that's right. Good. You're getting the hang of it. Now, Hide. Son: Hide? Why should I hide? I've done nothin' Dad: No, son, Hide, Hide, the Cow's outside. Son: Well, Don't bring the damned thing in!