"Did you hear the joke about the banana…

The “slipping on a banana peel joke” has been popular since the 1800s. A different kind of slippage—slipping one’s mind—has been cited in print since at least December 7, 1011:

First Actor—Why didn’t you spring that banana peel joke tonight?
Second Actor—Couldn’t. It slipped my mind.

7 December 1911, The York Daily (York, PA), pg. 4, col. 4:
Naturally
First Actor—Why didn’t you spring that banana peel joke tonight?
Second Actor—Couldn’t. It slipped my mind.

11 December 1911, The Rocky Mountain News (Denver, CO), pg. 6, col. 6:
Naturally
First Actor—Why didn’t you spring that banana peel joke tonight?
Second Actor—Couldn’t. It slipped my mind.

14 November 1926, Boston (MA) Sunday Globe, pg. 25 (?), col. 5:
NATURALLY
First Ham—Why didn’t you spring that banana peel joke tonight?
Second Ham—Couldn’t. It slipped my mind.

Google Books
The Zaniest Riddle Book in the World
By Joseph Rosenbloom
Illustrated by Sandy Hoffman
New York, NY: Sterling Publishing Company, Inc.
1984
Pg. 32:
Did you hear the joke about the banana peel?
Sorry, it must have slipped my mind.

13 April 2003, Toronto (ON) Star, “Peeling Back the History of Bananas,” pg. D16:
So, eat a banana and think about its long history. I’ll have to tell you my joke about the banana peel another time- it just slipped my mind.

Google Books
Funny-Side Up:
A Tasty Joke Book
By Chip Eliot
New York, NY: Scholastic
2008
Pg. 41:
Sandy: Did I tell you the one about the banana peel.
SpongeBob: No. Sandy: It must have slipped my mind.

Twitter
k.
@k___ena
Did you hear the joke about the banana peel? Nvm it slipped my mind. (I always get the gayest jokes)
6:43 PM - 12 Dec 2009

Twitter
Andrew Sedgwick
@ASedgy13
Did you hear the one about the banana peel?
Never mind, it slipped my mind
#badjokefriday
12:01 PM - 23 Mar 2018

“Did you hear the joke about the banana peel?”/“Sorry, it must have slipped my mind.”