A bus full of 50 ugly people (including the driver) is driving down a meandering mountain road. Suddenly, the bus careens out of control, falls of the cliff, and everyone on board dies instantly.
So these 50 ugly people are standing at the gates of heaven. St. Peter says "I'm sorry but there has been a mistake, you all died before your time. To make up for this minor inconvenience you will all get one wish to make your stay in heaven more enjoyable."
So, the first ugly person says "I want to be beautiful!" Their wish is granted, and they are beautiful.
The second person hears that and thinks that being beautiful sounds pretty damn good, so he says "I want to be beautiful, too!" Soon, all the ugly people are asking for the same wish.
As they go down the line the guy in the back starts to chuckle and as they move on his laughter gets louder.
By the time they get to the last guy, he's rolling on the ground, crying with laughter. St. Peter waits for the man to compose himself, then says "What is your wish, my son?"
The man then says, through stifled giggles, "Make 'em all ugly again!"