Knock, knock.
Who's there?
Ken.
Ken who?
Can you walk the dog for me?
Knock, knock.
Who's there?
Ken.
Ken who?
Can you walk the dog for me?
Listen up, buttercup! This joke plays on the sound of "Ken" and "Can." The last line is a question that sounds like "Can you walk the dog for me?" It's funny because it's unexpected and uses similar-sounding words to trick ya. Also, you probably can't walk a dog because you are dumb.