I have enclosed some Knock Knock jokes for your pleasure

Knock, knock!Who's there?Little Old Lady.Little Old Lady who?I didn't know you could yodel!
Knock, knock!Who's there?Doris.Doris who?Doris open, I'm going to come in.
Knock, knock!Who's there?Dwayne.Dwayne who?Dwayne the bathtub, I'm dwowning.(Drain the bathtub, I'm drowning.)
Knock, knock!Who's there?Cow go.Cow go who?Cow go moo!
Knock, knock!Who's there?Amos.Amos who?A mosquito bit me.
Knock, knock!Who's there?Euripides.Euripides who?Euripides pants and I won't make you another pair.
Knock, knock!Who's there?Keith.Keith who?Keith me, my thweet preenth.(Kiss me, my sweet prince.)
Knock, knock!Who's there?José.José who?José can you see by the dawn's early light?(Oh say can you see by the dawn's early light? -- first line of The Star-Spangled Banner)
Knock, knock!Who's there?Red.Red who?Its John Dunkely!(He has red hair!)
Knock, knock!Who's there?Ross Perot.Ross Perot who?See how quick people forget?
[edit] Puns on other words
Knock, knock!Who's there?Alpaca.Alpaca who?Alpaca the trunk, you pack-a the suitcase.
Knock, knock!Who's there?Beets.Beets who?Beets me.(Beats me.)
Knock, knock!Who's there?I love.I love who?I don't know, you tell me.
Knock, knock!Who's there?Orange.Orange who?Orange you going to open the door?(Aren't you going to open the door?)
Knock, knock!Who's there?Banana.Banana who?Knock, knock!Who's there?Banana.Banana who?Knock, knock!Who's there?Banana.Banana who?Knock, knock!Who's there?Orange.Orange who?Orange you glad I didn't say "banana"?(Aren't you glad I didn't say "banana"?)
Knock, knock!Who's there?Boo.Boo who? (Boo-hoo!)Don't cry; it's only a knock-knock joke.
Knock, knock!Who's there?Atch.Atch who?God bless you! (referring to sneezing sound,as in,"Achoo!").
Knock, knock!Who's there?Your friend, Stewie, and he'll always be there for you.
KNOCK KNOCKWho's There?BooBoo Who?Don't cry, its only a joke!
KNOCK KNOCKWho's There?RitaRita who?Rita book, you might learn something!
KNOCK KNOCKWho's There?HeavenHeaven who?Heaven you heard enough of these silly knock-knock jokes?
KNOCK KNOCKWho's There?LettuceLettuce who?Lettuce in, its cold outside!
KNOCK KNOCKWho's There?AnitaAnita who?Anita tissue....ah-choo! Too late!
KNOCK KNOCKWho's There?HoneycombHoneycomb Who?Honeycomb your hair!
KNOCK KNOCKWho's There?JustinJustin who?Just in time for dinner!
KNOCK KNOCKWho's There?CanoeCanoe who?Canoe come out to play?
KNOCK KNOCKWho's There?BeetsBeets who?Beets me!
KNOCK KNOCKWho's There?ArthurArthur who?Arthur more cookies in the jar?
KNOCK KNOCKWho's There?Honey BeeHoney Bee who?Honey, bee a dear and get me a soda.
KNOCK KNOCKWho's there?CowsCows who?No they don't, they MOO!
KNOCK KNOCK Who's There? Gorilla Gorilla who? Gorilla me a hamburger, I'm hungry!
KNOCK KNOCK Who's There? Tom Tom who? Tom on, you know who I am!
KNOCK KNOCK Who's There? Howard Howard who? Howard I know?
KNOCK KNOCK Who's There? Roach Roach who? Roach you a letter, did you get it?
KNOCK KNOCK Who's There? A boy who can't reach the doorbell!!!!
KNOCK KNOCK Who's There? Lettuce Lettuce who? Lettuce out of here!
Knock KnockWho's there?Aardvark!Aardvark who?Aardvark a hundred miles for one of your smiles!Knock KnockWho's there?Aaron!Aaron who!Aaron on the side of caution!Knock KnockWho's there?Abbott!Abbott who?Abbott time you answered the door!Knock KnockWho's there?Abe!Abe who?Abe C D E F G H...!Knock KnockWho's there?Abyssinia!Abyssinia who?Abyssinia behind bars one of these days!
Knock KnockWho's there?Acid!Acid who?Acid down and be quiet!Knock KnockWho's there?Ada!Ada who?Ada burger for lunch!Knock KnockWho's there?Adair!Adair who?Adair once but I'm bald now!Knock KnockWho's there?Adam!Adam who?Adam if I do and adam if I don't!Knock KnockWho's there?Adelia!Adelia who?Adelia the cards and we'll play snap!
Knock KnockWho's there?Adlai!Adlai who?Adlai a bet on that!Knock KnockWho's there?Adolf!Adolf who?Adolf ball hit me in the mouth!Knock KnockWho's there?Aesop!Aesop who?Aesop I saw a puddy cat!Knock KnockWho's there?Agatha!Agatha who?Agatha headache. Do you have an aspirin?Knock KnockWho's there?Agnes!Agnes who?Agnes & Topeka & the Santa Fe!
Knock KnockWho's there?Ahmed!Ahmed who?Ahmedeus Motzart!Knock KnockWho's there?Alaska!Alaska who?Alaska my friend the question then!Knock KnockWho's there?Aida!Aida who?Aida lot of sweets and now I've got tummy ache!Knock KnockWho's there?Al!Al who?Al give you a kiss if you open this door!Knock KnockWho's there?Aladdin!Aladdin who?Aladdin the street wants a word with you!