One popular bar joke is:
 
“A woman walked into a bar and ordered a double entendre, so the barman gave her one.”
 
It’s not known who originated the joke. “A girl waks into a bar and orders a Double entendre. So the barman gives her one” was cited in print in 1998.
 
   
Wikipedia: Meta-joke
Meta-joke refers to several somewhat different, but related categories: self-referential jokes, jokes about jokes (also known as metahumor), and joke templates.
 
Self-referential jokes
This kind of meta-joke is a joke in which a familiar class of jokes is part of the joke. Examples of meta-jokes:
(...)
. A woman walked into an English pub and asked the barman for a double entendre. So he gave her one.
. A woman walked into an American bar and asked the bartender for a double entendre. So he gave it to her.
     
Google Groups: alt.tasteless.jokes
This guy walks into a bar…
M.A. Porter
2/13/98
(...)
How about:
A girl waks into a bar and orders a Double entendre.
So the barman gives her one.
 
BBC News
Thursday, July 8, 1999 Published at 12:38 GMT 13:38 UK
Entertainment
Your jokes of the century
(...)
A woman walked into a bar and ordered a double entendre, so the barman gave her one.
Paul, UK
   
h2g2
The double entendre
Orcus
Posted Nov 11, 1999
(...)
Also, here’s a silly (and possibly crap - but who am I to comment) joke.
“A woman walks into a bar and asks the barman for a double entendre…
So he gives her one” Boom Boom.
 
Straight Dope Message Board
Double Entendres
Crusoe
11-27-1999, 06:57 PM
For your edification…
A woman walks into a bar and asks the barman for a double entendre. So he gives her one.
 
Google Groups: misc.writing
A woman walks into a bar and asks for a double entendre.
Blanche Nonken
10/2/01
So the bartender gives it to her.
 
Google Books
A Guy Walks Into A Bar…:
501 Bar Jokes, Stories, Anecdotes, Quips, Quotes, Riddles and Wisecracks
By Michael Lewis
New York, NY: Black Dog & Leventhal, Inc.
2005
Pg. 19:
A woman goes into a bar and asks for a Double Entendre. So the bartender gives her one.
 
Urban Dictionary
Double Entendre
A sentence/phrase with a double meaning (one of which is risque).
Double - Two
Entendre - Derived from the french word for intent.
Double Entendre - Intentionally giving a double meaning.
“A woman walks into a bar and asks for a double entendre, so the barman gives her one.”
(...)
by Silver Coin August 15, 2006
 
18 February 2012, The Herald Bulletin (Anderson, IN), “Someone will buy my toilet seat: Gene’s treatise on revulsion” by Gene Weingarten, pg. A10, col. 2:
Here are my two favorite jokes, which I have consigned to print several times:
 
Woman walks into a bar, says: “I’ll have an entendre. Make it a double.” So the bartender gives it to her.
 
Twitter
Rachel Pritchard
‏@returnswitch
A woman goes into a bar and asks for a double entendre, so the barman gives her one.
6:06 PM - 5 Jul 2014