People of all cultures have typically observed a mandatory day of rest. Most do it for religious reasons. However, as writer Judith Shulievitz found while researching the topic, the Sabbath holds unseen benefits that could be more important for the modern world than ever before.

Join Rick Horrow Sunday night with CNN's Don Lemon at 6 p.m. ET.

From Sports Business Analyst Rick Horrow:

Would watching sports be any fun if you couldn’t bet on them? Not for millions of us.

Consider this:
• An ESPN poll found that half of the 118 million Americans 16 and older have placed a bet on sports in the past year (including office pools), and 52 percent of those polled believe that “some sports are fixed.”
• All but two states – Hawaii and Utah – allow some form of gambling.
• Estimates peg the yearly amount of sports betting (legal and illegal) as reaching $300 billion – almost as much as the United States defense budget and more than the GDP of Switzerland.

The one thing college basketball, disgraced golfers, and dancing celebrities have in common is betting lines. Betting has become such a big part of our NCAA men’s basketball tournament ritual that according to a study released by the NCAA, the FBI estimates that over $2.5 billion is gambled illegally on March Madness games worldwide – despite threats of legal action against unlawful bettors in the states of Idaho and Washington.

In Las Vegas, March Madness is getting close to topping the Super Bowl – Vegas’ share is pegged at as much as $80-$90 million. This year, some sports books there are also charging a premium for guaranteed seating as well as their all-but-guaranteed handle. Lagasse’s Stadium at The Palazzo sells reserved seats with a minimum of $125 in food purchases, while the Wynn/Encore and Planet Hollywood reportedly charge $25 per day.

While Vegas casinos may show a full house during March Madness, online gambling sites are also busier than ever. Bettors in the U.S. account for close to half of the world estimated total of $18.4 billion wagered in Internet gambling.

It’s not all about basketball, of course. Gambling odds on Ernie Els are dropping since The Big Easy has won the PGA Tour’s last two events – Els is currently at 12-1 to win The Masters, according to stats from The Palazzo. Tiger Woods is the favorite to win The Masters at 9-2, but it’s a lot more fun to consider the wacky “prop” bets British bookmakers are taking on Tiger: Will he hit a tree, get into a fight with a fan, kiss an anonymous blonde? And bets about whether wife Elin will appear at The Masters just got a lot more interesting after she was photographed at the Sony Ericsson Open in Miami, not in Sweden with relatives as had previously been speculated.

Even "Dancing With The Stars" is fair game. Betting odds for the current season, jam packed with jocks, have been "astronomical," according to Gambling911.com. Gambling website BetUS.com has Olympic gold medal skater Evan Lysacek as its +200 odds co-favorite to win it all.

Might not be a coincidence that the latest “Dancing With The Stars” season kicked off right in the middle of March Madness.

Rick Horrow is a regular contributor to CNN as a Sports Business Analyst and co-author of "Beyond the Box Score: An Insider’s Guide to the $750 Billion Business of Sports" (Morgan James, March 2010)