by Leif Jacobsson of Sweden, or Nazir from the Pages of Prophecy BBS

 How many Forsaken do you need to change a lightbulb?

All 13!
Aginor to attempt to breed a new kind of Shadowspawn that is optimized to replace bulbs,
Balthamel to go to find a maid, to find one, and to not return,
Belal to try to manipulate someone else into doing it,
Ishamel to start a philosophical/theological debate about how this shows that the Dark One is stronger than the Creator,
Lanfear to leave, furious that noone can see how gorgeous she is,
Rahvin to use the darkness to sneak away with the maid that Belal manipulated into changing the bulb,
Asmodean to go to Rhuidean to search for a ter'angreal who can revive dead lightbulbs,
Sammael to discover that he's too short to reach the bulb, and to find and kill the architect who designed the room,
Moghedien to masque herself as a maid and to spy on the others while she is "unsuccessfully" attempting to change it,
Mesaana to hold a lecture about the history, theory and philosophy behind electricity in common and bulbs in particular,
Semiraghe to torture the servant who let the bulb burn out,
Demandred to change into his disguise and slip away unnoticed,
and Graendel to use compulsion to turn a handsome young man and a strikingly beautiful young woman into the happiest bulb switchers in the whole world!

How many Tairens do you need to change a lightbulb?

One, if you can convince him that Illianers like dark rooms…

How many Illianers do you need to change a lightbulb?

One, if you can convince him that Tairens like dark rooms…

How many Aiel do you need to change a lightbulb?

None, they let the Gai'shain do it for them.

How many Darkfriends do you need to change a lightbulb?

None, Darkfriends are friends of the dark. 

How many Aes Sedai do you need to change a lightbulb?

58!
A blue to try to manipulate an innocent bystander into changing it, 
a second blue to try to manipulate the first blue to do it,
a grey to settle the conflict between the two blues,
a white to try to prove logically that the bulb shouldn't be changed because darkness is a natural state indoors at night, 
a second white to try to prove logically that the first white is an idiot, 
a second and a third grey to calm the two whites down as they dispassionetly, non-emotionally, logically and coolly try to scratch each other's eyes out,
a brown to go away to try to find some ancient instructions in the library and to not return this month, 
a red to complain that this would never have happened if the bulb had been invented by a woman, 
another red to agree, 
a third red (black in secret) to try to convince the others that the easiest way to stop all men that can channel is to kill all men in the world,
a second brown to look suspiciously on the third red,
a third white to nod to the second brown, 
a dozen sisters of mixed colors to shield, haul away, interrogate, still and execute the third red,
thirteen other blacks to flee the tower,
thirteen more reds to locate and gentle the man who had channeled so that the bulb went out, 
a green to try to "privately convince" a handsome young man to change it,
a second green to try to "privately convince" another handsome young man to change it, 
three more greens trying to "convince" one handsome young man each (just in case), 
one yellow to revive the lamp, 
and a fifteenth black to kill it again as soon as the coast is clear

Raina's Hold / Raina's Library / Raina's Library - Other People's Humour