A popular Halloween ghost riddle is:
 
Q: What do ghosts read at a concert?
A: Sheet music.
 
“What music do ghosts prefer? Sheet music” was printed in several newspapers in October 1981.
 
   
25 October 1981, Mobile (AL) Press Register, “Junior Whirl” by Hal Kaufman, comic sec., pg. ?, col. 2:
Halloween Fun! What music do ghosts prefer? Sheet music.
 
30 October 1984, St. Louis (MO) Post-Dispatch, “Riddle-Me-Crazy,” pg. 4F, col. 5:
Q: What kind of music do ghosts prefer?
A: Sheet music.
 
Google Groups: alt.folklore.ghost-stories
Halloween/Moster Jokes! YAAY!
Erica B
10/14/99
(...)
What kind of music do ghosts listen to?
Sheet music.
 
Google Books
Spooky Sillies:
A Book of Ghost Jokes
By Mark Moore
Illustrated by Anne Haberstroh
Minneapolis, MN: Picture Window Books
2005
Pg. 16:
What do ghosts read at a concert?
Sheet music.
 
Google Books
Extreme Monsters Joke Book
By Nikki Bataille Lange
Illustrated by Tim Stuby
Columbus, OH: Brighter Minds Children’s Publishing
2005
Pg. 39:
How do ghosts learn songs?
Thev read the sheet music!
 
Google Books
Joke & Riddle Ballyhoo
By Jacqueline Horsfall
Illustrated by Jackie Snider
New York, NY: Sterling Publishing Company, Inc.
2005
Pg. 29:
What do ghosts read during band practice?
Sheet music.
   
Google Groups: nl.regio.wadden
bear alert
Aagje-Meu
8/28/06
(...)
Q: How do ghosts learn songs ?
A: They read the sheet music !
 
Google Books
Laughin’ Jammin’ Slammin’ Jokefest
By Jacqueline Horsfall and Terry Pierce
New York, NY: Sterling Publishing Company, Inc.
2007
Pg. 195:
What do ghosts read during band practice?
Sheet music.
 
Twitter
Sherri Stevens
‏@carly300
@ImMattGiraud What type of music do ghosts listen to?  Sheet music
7:52 PM - 17 Oct 2009
 
Twitter
Daily Groaner
‏@DailyGroaner
Q: How do ghosts learn songs? A: They read the sheet music!
7:33 PM - 19 Oct 2009
 
Google Books
Screaming with Laughter:
Jokes about Ghosts, Ghouls, Zombies, Dinosaurs, Bugs, and Other Scary Creatures
By Michael Dahl
Mankato, MN: Picture Window Books
2011
Pg. 66:
What do ghosts read at a concert?
Sheet music.
 
Twitter
🌟
‏@harrouy
@LarrySexGods What kind of music does a ghost read in band?

      👻 Sheet music 👻
4:17 PM - 8 Jan 2014
   
Google Books
Halloween Ghost Jokes For Kids
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
How do ghosts learn songs?
They read the sheet music!