Singers have popular jokes on how many it takes to screw in a lightbulb:
 
Q: How many sopranos does it take to change a lightbulb?
A: One. She holds the bulb and the world revolves around her.
A: Two. One to hold the diet cola and the other to get her accompanist to do it.
A: Four. One to change the bulb and three to pull the chair out from under her.
 
The joke has been cited in print since at least 1991. Related jokes include “How many altos does it take to screw in a light bulb?” and “How many tenors does it take to screw in a light bulb?”
         
   
Google Groups: rec.music.classical
Musical Jokes Wanted
houston dunleavy
2/24/91
Q. How many sopranos does it take to change a light bulb?
A. Eight. One to do it and seven to sit back a say that they could have got just as high as her.
 
Google Groups: rec.humor
Lightbulb Jokes
Kevin Nechodom
7/19/91
Heard at same university’s College of Fine Arts:
Q:  How many sopranos does it take to screw in a lightbulb?
A:  3; One to do it, and the other two to kick the ladder out from under her
   
Google Books
Musical Opinion
Volume 115
1992
Pg. 278:
Q. How many sopranos does it take to change a lightbulb?
A. Four. One to change the bulb and three to kick the chair from under her.
Q. How many altos?
A. Five. One to change the bulb and four to complain that it was too high.
Q. Tenors?
A. Six. One to change the bulb and five to complain that they weren’t asked.
Q. And Basses?
A. As many as you like, because none of them will show up on the day.
 
Google Groups: rec.humor
WANTED - Lightbulb jokes
Mark Rimple
9/4/94
Here’s a musical one. 
 
How many Sopranos does it take to screw in a light-bulb? 
One.  She just stands with the light-bulb in her hand, and the whole world turns around her.
 
Google Groups: rec.music.makers.choral
Choral Humour
Lucas M Weiss
2/8/97
Q: Why are altos always locked out of their houses?
A:  because they can’t find the key and they don’t know how to come in.
Q: How many sopranos does it take to screw in a litebulb?
A:  One.  She holds the lightbulb and the world revolves around her.
Q:  How many Altos does it take to screw in a lightbulb?
A:  They can’t reach that high.
 
Google Books
Getting Opera:
A Guide for the Cultured But Confused
By Matt Dobkin
New York, NY: Pocket Books(Simon & Schuster)
2000
Pg. 10:
How many sopranos does it take to change a lightbulb?
Just one. She just holds it in place, and the whole world revolves around her.
 
Google Books
Why Did the Chicken Cross the Road?
By Paolo Agnoli and Patrizia Di Nicola
Rome: Armando editore
2001
Pg. 102:
How many sopranos does it take to change a light bulb?
Three. One to climb up the ladder, one to kick the ladder out from under her and a third to say, “I knew that was too high for you dear”.
 
Google Books
The Best Musicians’ Jokes
By Bruno Kassel and Carlo May
Pacific, MO: Mel Bay Publications, Inc.
2005
Pg. 95:
How many sopranos does it take to change a Iightbulb?
Two. One to hold the diet cola and the other to get her accompanist to do it.