A popular “Yo’ mama joke is:
 
“Yo’ mama is so dumb, when your dad said it was chilly outside, she ran out with a spoon.”
     
The joke has been cited in print since at least 1993.
 
   
Google Groups: rec.humor
Insults
Nathan Mates
2/15/93
(...)
Your Mama’s So stupid, when your dad said it was chilly outside, she ran outside with a spoon
 
Google Groups: alt.tasteless.jokes
Your Mother ...
Joe Klein, I3.KI 2675
5/26/93
(...)
stupid, when your dad said it was chilly outside, she ran outside with a spoon
   
Google Groups: alt.tasteless.jokes
YOUR MAMA
JOEL ENNIS
10/5/93
(...)
THE OTHER DAY I TOLD YOUR MAMA IT WAS CHILLY OUTSIDE AND SHE GOT A SPOON
 
Google Books
Over 1500 Fantastic Jokes
By Guy Campbell and Paul Moran
London: Dean
2002
Pg. 255:
When your Mum said it was chilly outside, he ran outside with a spoon.
 
Google Books
A Prairie Home Companion
Pretty Good Joke Book
By Brian Becker
Minneapolis, MN: HighBridge
2003
Pg. 79:
Yo’ mama is so dumb, when your dad said it was chilly outside, she ran out with a spoon.
 
Google Books
Yo’ Mama Is So…:
892 Insults, Comebacks, Putdowns, and Wisecracks About Yo’ Whole Family
By Hugh Payne
New York, NY: Black Dog & Leventhal Publishers, Inc.
2007
Pg. 16:
When yo’ daddy said it was chilly outside, yo’ mama ran out with a spoon.
 
Twitter
ink by Push
‏@ArtByPush
@DJKISSBEATS Yo mama is so fat AND stupid, ur dad said it was chilly outside so she ran outside with a spoon!
8:32 PM - 2 Jul 2009
 
Twitter
Ty Is_Opinionated
‏@621PretttyTy
Ya momma is so dumb, I told her it was chilly outside. She went to get a spoon.
12:11 PM - 9 Mar 2016
 
Twitter
NBA on TNTVerified account
‏@NBAonTNT
Ernie’s got #jokes
YOUR MOTHER IS SO UNEDUCATED THAT SHE RAN FOR A SPOON WHEN SHE HEARD IT WAS ‘CHILLY’ OUTSIDE
8:23 PM - 27 Apr 2016