I'm not sure what the policy is on printing our own material, after submitting and publishing on another website. SO let me first just refer you to the Modern Humorist version of this piece, and give them some huge props for recognizing genius when they see it. Hee!  

Read it there, then read the unedited version below.

Throughout the tumultuous labyrinth of human history, there have been few pieces of cultural iconography able to withstand the turbulent course mankind has traveled. One seemingly eternal bit of interpersonal contact that has bonded modern man to his ancestors is the “knock-knock joke”. As long as people have been entering and exiting buildings, they have been taking this deceptively commonplace activity and “sprucing it up” with the world’s oldest tension relieving device: laughter.

Our modern day celebrities may be exempt from parking tickets, household chores, and murder charges, but as long as hotels, limousines, and crack houses are equipped with a door or other entryway that is conducive to “knocking”, celebrities will not find themselves immune to this classic tomfoolery. What follows is the “cream of the crop” of what historian Arnold Toynbee would have called, “celebrity Knock-Knock Jokes”

Knock Knock.
Who's there?
Major Dad.
Major Dad who?
Major Dad go down on me.

Knock Knock.
Who's there?
Tempest Bledsoe.
Tempest Bledsoe who?
Tempest Bledsoe much she passed out.

Knock Knock.
Who's there?
Richard Pryor.
Richard Pryor who?
Richard Pryor hands off that crack pipe.

Knock Knock.
Who's there?
Mel Gibson.
Mel Gibson who?
Mel Gibson incredible blow job.