Knock knock. Who is there? Lettuce. Lettuce who? Lettuce in, it is cold out here! The vegetable had been standing outside for twenty minutes and was absolutely freezing.

Knock knock. Who is there? Cow says. Cow says who? No silly, cow says MOO! The farmer at the door had heard this one a hundred times but still laughed every time.

Knock knock. Who is there? Olive. Olive who? Olive you and I miss you! The other person opened the door immediately - no one can resist that kind of declaration.

Knock knock. Who is there? Boo. Boo who? Do not cry, it is just a joke! The ghost at the door felt terrible about making anyone sad and apologized immediately.

Knock knock. Who is there? Interrupting cow. Interrupting cow wh - MOO! The timing is everything with this one - the moo has to land before the question finishes.

Knock knock. Who is there? Atch. Atch who? Bless you! The visitor had been holding that sneeze in for quite some time and was very relieved to let it out.

Knock knock. Who is there? Nanna. Nanna who? Nanna your business! Grandma always said if you do not want to be interrupted, do not answer the door.

Why is the sky blue? Because if it were green, you would not know where to stop mowing the lawn! Every kid who asks this gets one of two answers: a physics lecture or complete silence.

What do monsters put on their bagels? Scream cheese! It comes in classic, strawberry, and terrifying - all equally spreadable. The monster under the bed prefers the garlic flavor, ironically.

What do you call a superhero who cannot fly? A walkhero! They still save the day - it just takes a bit longer and they need good sneakers. The commute to emergencies is very inconvenient.