"He is the person who could go from talking about a book that just came out to telling a knock-knock joke from sixth grade."

The group's name came from a nonsensical knock-knock joke Drucker's sister told him when she was five years old.

I figured this wasn't the time for knock-knock jokes.

And knock-knock jokes are for "kids," or so say the 11-and-older set.

You're in and out of a studio meeting - as fast as a knock-knock joke.

I find the book, turn to answer Jason, then face Maya, who is fast approaching with a new knock-knock joke.

It's what makes people smile mistily at me, as if I'm fading in front of their very eyes while telling knock-knock jokes.

One of the stalls had a running series of knock-knock jokes.

A knock-knock joke is always included as a part of this feature.

Dishes the very last knock-knock joke in this book.