Mega Millions jackpot set to skyrocket to new milestone if no winner Tuesday

The largest jackpot in U.S. lottery history could be decided Tuesday night.

Up for grabs is $1.6 billion in the Mega Millions lotto. The cash payout? $913.7 million.

That jackpot could soar to $2 billion if there's no winner, according to the Maryland and Texas Lotteries.

That means the lump sum payout would rise to $1.142 billion.

The odds of winning the $1.6 billion jackpot are currently 1 in 302,575,350, but that hasn't stopped thousands of people from playing across the country.

Those slim chances don't seem to be putting a damper on the excitement for some folks, including Marissa Kagan, who waited in line at a store near Primm, Nevada, for a while.

"I've been waiting an hour and a half," said Kagan. "Once you've made the trip from Vegas, you might as well just stay for the duration."

"I never play, but we just kind of figured 'why not?'" Kagan said, noting that if she wins, she said that she would buy a school and build some homeless shelters.

Christina Nagar, a fellow Las Vegas resident who was on line at the same store, said that she would "buy a few penthouses" as well as some "new cars, a bunch of sneakers."

Andres Ojeda, who was also in line at the store, had less firm plans for the jackpot.

"I don't know, but I'd like to find out!" Ojeda said.

ABC News' Justin Doom contributed to this report.

Cox Media Group