Courtesy of The Boondock Saints:

(which you should all know is a good movie..and i just found out theyre making a sequel..hurrah!..anyways the joke...)

There's these three guys walking on the beach, a mexican, a white guy, and a black guy. So they find this pot, rub it, and a genie comes out. The genie says you can wish for whatever you want. So he asks the Mexican what he wants, and he says "I want all my people in America to be happy and free, and in Mexico." So the genie goes poof! It's done. Then he says to the black guy "What do you want?" And the black guy says "I want all my brothers and sisters to be back in Africa, and happy and free and everything." So the genie goes poof! And they're all back in Africa. So the genie says to the white guy, "What's your one wish?" And the white guy says, "Wait, you mean to tell me that all the mexicans and blacks are out of America?" The genie goes yeah, and the white guy says, uh, "I'll have a Coke, then."