Have you heard the one about…?
Definition 1 of 1
Pro Tip 1/3Setup Expectation
This phrase indicates you're about to tell a joke, preparing listeners for humor. 
Hey, have you heard the one about the scientist? It'll have you laughing in the lab!
Pro Tip 2/3Informal Use
It's casual and best used in informal settings with friends or family. 
At the family BBQ, Uncle Joe asked, 'Have you heard the one about the skunk?'
Pro Tip 3/3Humor Icebreaker
Starting a conversation with this phrase can lighten the mood and make people laugh. 
During a break, Jake said, 'Have you heard the one about the broken pencil?'