I haven't heard all the lessons, but I was listening to season 3 lesson 21 and it made me laugh during my otherwise serious studying.
I really love the doctor's attitude. it makes me grin every time.
http://www.koreanclass101.com/learningcenter/lessons/newbie_lesson_s3_21/
What lesson dialogs make you laugh out loud?
What is your favorite multi-lesson story?
-edit-
maybe I am just tired. But I found 22 and 23 to be really funny as well.