You: I heard the funniest fucking knock knock joke the other day. Do you want to hear it? (Start out with this or preface with a story of your choice)
Other Person: OK
You: But you have to start it.
Other Person: Ok....Knock Knock
You: Who's there (Stare at them blankly waiting for them to finish the joke)
I fucking died laughing when a friend got some random girl at the bar with that last week. I'm amused easily, especially when I'm drunk.