It's the one day when many Americans gladly take a gamble: Super Bowl Sunday.
As the Denver Broncos meet the Carolina Panthers in Super Bowl 50 this Sunday, millions of people will place some type of bet on the game even if they don't care about football.
A minority will gamble legally at Nevada's casinos but most will make friendly, if often illegal, wagers at their workplace, corner bar or Super Bowl house party. Even those careful with a dollar often plunk down $10 for a square in the office pool.
"A lot of people bet on only one game the entire season, and this is the one," said Jay Kornegay, director of the sports book at the Westgate Las Vegas Resort & Casino.
They'll bet not only on which team will win this year's game at Levi's Stadium in Santa Clara, Calif., but on a myriad of other scenarios related to the big event — maybe the pregame coin toss or how long it takes to sing the national anthem.
Add it up and Americans will spend at least $4.2 billion betting on the Super Bowl this year, the American Gaming Assn., a casino trade group, estimated last week.
It's widely agreed that no other single U.S. sporting event commands such betting, and the sports website Pregame.com estimates that more than half of adult Americans will have some money at risk on Sunday's game.
Using the gaming association's estimate, the Super Bowl bets legally placed at Nevada's casinos amount to a mere 2.8% of the total wagered nationwide, most of which is private and unlicensed.
Moreover, the group also believes its figure is "a conservative estimate" and that the actual dollar amount wagered on the Super Bowl probably is higher, association spokesman Chris Moyer said.
"No one can say with pinpoint accuracy" how much is bet, he said.
Except at Nevada's casinos, where regulators keep a close eye on the action. Gamblers placed $116 million in bets on the Super Bowl last year through the casinos' sports books, according to the Nevada Gaming Control Board.
The New England Patriots defeated the Seattle Seahawks in that game, 28-24. But untold millions of dollars changed hands among bettors in the final minute when, just as Seattle appeared set to score the go-ahead touchdown, New England's Malcolm Butler intercepted a pass to preserve the Patriots' victory.
The amount wagered in Nevada last year was down 3% from the record $119.4 million bet on the Super Bowl in 2014. But the betting volume generally has increased in recent years in step with the U.S. economy's improvement from the severe recession.
Super Bowl gambling at the Nevada sports books has more than doubled in the last 22 years. The figure was $54.5 million in 1994 when the Dallas Cowboys defeated the Buffalo Bills, 30-13.
That's not surprising because the Super Bowl itself "has become so much of a social and cultural event for Americans," said David Schwartz, director of the Center for Gaming Research at the University of Nevada Las Vegas.
A record 114.4 million Americans watched last year's game, and "there's just a sense of the atmosphere around it, it's almost like a holiday," Schwartz said.
Just as many people watch the game mainly to see the new TV commercials, placing a bet also is widely considered part of the festivities, he said.
But for those betting at Nevada's casinos, wagering on sports generally has one of the lowest winning percentages compared with other forms of gambling, gaming board figures show.
Sports' winning percentage was 5.8% last year, compared with 18% for roulette and 12% for blackjack. Even slot machines, with an average winning percentage of 6.4%, have a better payout than sports.
The American Gaming Assn. started estimating the total amount of Super Bowl gambling last year mainly to raise awareness of how much illegal gambling occurs and whether state and federal gaming laws need to be changed.
The group's purpose, after all, is to represent the legal casino industry and funnel more betting its way. But Moyer said the effort was aimed more toward curbing large-scale illegal betting. "We're not talking about those harmless office pools" that are "relatively low-dollar figures and fun," he said.
There is no federal law against making bets on sports, but about half the states, including California, "have ancient laws on the books saying you can't make a bet," said I. Nelson Rose, a law professor and gaming expert at Whittier Law School.
Those laws "of course are never enforced" at places such as bars and backyard Super Bowl parties, he said. Betting on horse racing is legal because it's "expressly carved out on the federal and state level" to allow parimutuel gambling, Rose said.
Some of those state laws also are now being tested by the increasingly popular daily fantasy sports business, led by DraftKings and FanDuel. But those companies maintain that their contests are games of skill and not gambling.
Fantasy entrants draft professional athletes for their virtual teams and then, using points based on the athletes' real-world performances, calculate how their virtual teams finish.
Because the Super Bowl has only two teams from which to draft, DraftKings and FanDuel combine the National Football League's Pro Bowl and the Super Bowl into a single contest.
In betting on the Super Bowl, many Americans enjoy so-called proposition wagers, or prop bets, that in some cases have nothing to do with how the two teams play.
Kornegay said the Westgate Las Vegas casino will have nearly 400 prop bets for Sunday's game, and they'll generate about 60% of the total dollars wagered on the contest.
"We expanded the prop menu years ago because the games were so boring" and the prop bets help keep fans entertained even if the score is lopsided, Kornegay said. "Certainly they have become a big part of Super Bowl weekend."
Among the popular prop bets: which team will win the coin toss, which team will score the first (or last) touchdown and which team will draw the first penalty.
"I've also heard of people throwing prop parties when they get together in groups" for the game, Kornegay said. "They have a lot of fun with them."
And they will wager billions of dollars in the process as the Broncos and Panthers battle. But trying to count the exact amount of Super Bowl betting is "nearly impossible," Schwartz said.
"I don't have an estimate," Schwartz said. "It hurts my brain to even think about it."