A fortune cookie riddle is:
 
Q: What do you call a funny fortune cookie?
A: An inside joke.
 
The joke was posted on Reddit—Jokes on May 25, 2017.
 
   
Wikipedia: Fortune cookie
A fortune cookie is a crisp cookie usually made from flour, sugar, vanilla, and sesame seed oil with a piece of paper inside, a “fortune”, on which is an aphorism, or a vague prophecy. The message inside may also include a Chinese phrase with translation and/or a list of lucky numbers used by some as lottery numbers, some of which have become actual winning numbers. Fortune cookies are often served as a dessert in Chinese restaurants in the United States and other Western countries, but are not a tradition in China. The exact origin of fortune cookies is unclear, though various immigrant groups in California claim to have popularized them in the early 20th century. They most likely originated from cookies made by Japanese immigrants to the United States in the late 19th or early 20th century. The Japanese version did not have the Chinese lucky numbers and was eaten with tea.
     
Twitter
dv.erx‏
@dvners
Just Came Back From Watchinq Mikey mouse On Thee Ice Snappin..!Lol (Fortune Cookie)Inside Joke.! (:
9:18 PM - 30 Jan 2010
 
Twitter
qlp‏
@Requisite180
The All-thing inside-joke started by a Engrish fortune cookie; now a really amusing running gag. #forlaughs #simplethings #happiness
11:06 PM - 6 Jan 2015
 
Twitter
Mari‏
@marijuoanna
fortune cookie says ‘‘keep me and fortune will always be with you.’’ and i said ‘‘that’s an inside joke.’’ comedy from fortune cookies!
2:56 PM - 16 May 2015
 
Twitter
Adam Katz‏
@adam_katz14
When you have an inside joke with a fortune cookie #merryjewmas #myonlyfriendisacookie
9:29 PM - 25 Dec 2015
 
Reddit—Jokes
What do you call a funny fortune cookie?
submitted May 25, 2017 by Ninjabr3ad5lic3r
An inside joke