Scammers are calling people telling them that they have won a sweepstakes sponsored by the Make A Wish Foundation. This scam preys on the victims trust of the good name of the company that the scammers are hiding behind. There was a full article on this that you can read here.
Remember, you have to enter a sweepstakes in order to win, and if there are any fees connected with your winnings a legitimate company could take those fees from your winnings. You would never need to wire them any such fees.