The jackpot for tonight’s Mega Millions drawing has climbed to $636 million — making it the second-largest jackpot on the list of world record lotto prizes. Strong sales in Iowa and across the country pushed the estimated jackpot higher, up from an initial forecast of $550 million.

Iowa Lottery CEO Terry Rich says a lot of Iowans are hoping to becoming multi-millionaires later tonight. “The last draw on Mega Millions, we had over 80,000 people win (some type of prize) just in Iowa,” Rich says. “That big jackpot…the odds are huge, but it’s fun to dream a little for just a buck.”

If the game doesn’t have a jackpot winner tonight or Friday, it could grow to one-billion dollars ($1 billion) next week. “The problem with a billion dollars for the Iowa Lottery is our billboards don’t go that high,” Rich says. “We’re trying to scramble to figure out if it does, what do we do with all those numbers?” The Mega Millions jackpot was last won in the drawing on October 1st with a ticket sold in Maryland, so it’s been growing for more than two months.

Rich says Iowa is no stranger to big jackpot winners. Twenty workers at Quaker Oats in Cedar Rapids split a $240 million lottery jackpot last year, while a couple in Bondurant also claimed a $202 million Powerball prize in 2012. The deadline for buying a ticket for tonight’s drawing is 8:59 p.m.

(Reporting by Darin Swenson, KDEC, Decorah)