I'm trying to tell a joke, as if in a car full of drunk people. I'm trying to make something of a knock-knock joke I heard that day, involving Putin and Obama, whose punchline is "Crimea River". But I tell it like this:

"Knock knock"

"Who's there"

"Madame Curie"

"Madame Curie who?"

"Madame Curie a River!"

Then I realize I got it wrong...