A salesman telephoned a household, and a four-year-old boy answered. Salesman: "May I speak to your mother?"

Boy: "She's not here right now."

Salesman: "Well, is anyone else there?"

Boy: "My sister."

Salesman: "O.K., fine. May I speak to her?"

Boy: "I guess so."

At this point there was a very long silence on the phone.

Then:

Boy: "Hello?"

Salesman: "It's you. I thought you were going to call your sister."

Boy: "I tried. But I can't get her out of the playpen."