An oldie, but a good 'un...
Queen Elizabeth and Dolly Parton die on the same day, and they both go before St. Peter to find out if they'll be admitted to heaven.
Unfortunately, there's only one space left that day, so St. Peter has the unenviable task of deciding which of them gets in. The angel asks Dolly if there's a particular reason why she should be favoured over HRH, whereupon she takes off her blouse, undoes her bra and releases her enormous breasts.
"Look at these" Dolly says proudly, "they're the most perfect breasts that God ever created for a woman, so I should be the one to enter heaven."
The angel thanks Dolly, and asks Her Majesty the same question. The Queen takes a bottle of Perrier out of her purse, shakes it up, and gargles. Then, she spits into the toilet, and pulls the lever.
St. Peter bows slightly and says in a quiet voice, "OK, your Majesty, you may enter."
Dolly is outraged and asks, "What the h*ll was that all about? I show you two of God's own perfect creations, and you turn me down. She simply gargles, spits and she gets in. Would you explain that to me?"
"Sorry, Dolly," says St. Peter, "but even in Heaven, a royal flush always beats a pair, no matter how big they are."