You can google the sweep by name and rules will show on the respective sponsor site. You can also keep you own records and have an approximate date for winner picks.
And the Grinch, with his Grinch-feet ice cold in the snow, stood puzzling and puzzling, how could it be so? It came without ribbons. It came without tags. It came without packages, boxes or bags. And he puzzled and puzzled 'till his puzzler was sore. Then the Grinch thought of something he hadn't before. What if Christmas, he thought, doesn't come from a store. What if Christmas, perhaps, means a little bit more. - Dr. Seuss
May the Joy and the Meaning of the Christmas Season fill your hearts throughout the year.