AP Photo/G-Jun YamThe Mega Millions jackpot climbed to $1 billion ahead of a Christmas Eve drawing.If someone wins on Tuesday, they will score the seventh-largest prize in the game's history.The lump sum cash option is about $448.8 million, according to the Mega Millions website.One lucky lotto player could wake up to a billion-dollar Christmas morning this year.The Mega Millions jackpot hit an estimated $1 billion on Tuesday ahead of the Christmas Eve drawing, according to the Mega Millions website.If someone does score a six-number winning ticket on Tuesday, the jackpot would be the largest prize ever won in December and the seventh-largest in the game's history.Choosing the lump sum cash option would cut the prize money in half to about $448.8 million, according to the Mega Millions website.