Let's Crack A Joke

This past week, almost everyday, J would say to me while we are on the road to his school "Mom, let's tell some jokes."
(Sorry, he does not know yet that he can say, let's crack a joke.)

Most of the time, my mind would just go blank, because really there is no joke there.
"Mommy, it is just a joke."
"I don't know how to tell the joke." (I just realize that I become too serious in my adult life,, sad  :-()
"You can read it from my imaginary book."
Oops, where is that book, and how I am surposed to read it.
Have to find another execuse.
"But I don't know the imaginary language."
"It is written in English."
"Really?"
"Yeah, it is also in Chinese."

Thank you dear son for being so considerate by offering me your imaginary book written in both English and Chinese. But I was really strugggling on how to read it..:-(
Have to make up something now.
"There was a bear walking and ran into a rabbit.." honestly speaking, I really did not know what I was talking about. :-(

And the end result, I went to Chapters with J to look for some kids joke books.