banana, who?

our conversation at dinner tonight:

madeleine: mom, do you want to play knock knock?
me: sure.
madeleine: okay, your turn.

me: knock knock.
madeleine: who's there?
me: banana.
madeleine: banana, who?
me: knock knock.
madeleine: pauses and looks at me strangely. that's not how you do it.
randy: that's the most classic knock knock joke there is, madeleine.
me: fine, your turn, madeleine.

madeleine: knock knock.
me: who's there?
madeleine: orangie.
me: orangie, who?
madeleine: michael!
the girls erupt in laughter.

me: knock knock.
madeleine: who's there?
me: henrietta, the rude interrupting cow. 
madeleine: pauses and looks at me strangely. that's not a name.
me: fine, your turn again.

madeleine: knock knock.
me: who's there?
madeleine: um, cup (i was holding a cup. this girl doesn't go far for her inspiration).
me: cup, who?
madeleine: stringy!
more uncontrollable laughter from the girls.