Knock Knock

We have been having fun with knock knock jokes lately. One boy from the playground tests me each day to see if I have a new one. He laughs weather he gets it or not, but it's pretty funny to see his face when he actually does. But this week's funny-Superman-story will knock your socks off, Superman likes to talk to himself on the telephone. He picks up a toy phone and this is how the conversation goes:
"Hello, Superman"
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"Is Superman there?"
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"Tell me a knock knock joke."
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"Who's there?
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"Boo who?"
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"Ha Ha Ha"
Want something funny about Mimi? She has a silly eating habit involving cereal. She picks up a spoonful of Cheerios and milk, flicks out the Cheerios and slurps up the milk. The radius of Cheerios is about 5 ft.
Mimi is tall and skinny for age, I tell them both: "eat more, you're too skinny!" Superman says back to me "no, you're too skinny!" and I say "thank you!"