A news feed from the CNW group describes a video feed that will come from Disney on October 4 at 10:30AM EDT. From the news feed:
The family will enter the Magic Kingdom and walk into a completely empty
park with no other guests around. A red-carpet will line the entire length of
Main Street U.S.A. creating a true VIP moment for the family. As they walk
down the red carpet heading to Cinderella Castle, hundreds of Disney cast
members and characters will rush out to greet them and welcome them in true
Disney style.
As the family continues their private adventure through the Magic Kingdom
they will be able to enjoy all the attractions – all by themselves! Later in
the day, when the park opens to guests, the family will serve as the grand
marshal of the Disney Dreams parade. Their dream day will be capped off with a private viewing of the Walt Disney World spectacular fireworks show, “Wishes.”
I had previously, mistakenly thought that this was a prize somebody would win the previous day, probably in the parks . . . turns out the prize was awarded some time back and the winner has kept the secret to themself. (There’s a thread on the DISboard with more details.)
Broke Hoedown 
Color me envious! Here’s a link to the story of the lucky family from Ohio:
http://www.wftv.com/news/9999686/detail.html#