A conversation I had with Hubs last night:

Wifey: “Do you have a ruler I could borrow?”
Hubs: “How long do you need it?”
Wifey: “10 or 15 minutes?”
Hubs: (looking bemused) “No, what LENGTH do you need it?”
Wifey: (laughing very hard) “Oh! 15cm should do the trick.”

I laughed about that for the rest of the evening.