Time is running out to fill out your NCAA tournament bracket. For some, that means crunching statistics, scouring injury reports and searching for historical trends. For everyone else, it begs the question, What is this all about?

The simple answer to that is: money. In 2010, CBS and Turner Sports paid $14 billion — with a “B” — for the rights to televise the NCAA tournament. Why? Because it is one of the most popular sports events on the calendar. Why? Well, the NCAA might tell you about the opportunities for student-athletes from diverse educational institutions in an egalitarian format in which Wofford College is given the same competitive opportunity as the University of Michigan.

But the real reason for the NCAA tournament’s popularity is that it’s an easy and fun event to gamble on. An estimated 50 million Americans wager an estimated $3 billion in college basketball pools every year, and winning doesn’t have all that much to do with knowledge. So it’s sort of like the lottery, but you can watch it on TV.

Is the allure still not clear? A quick vocabulary primer will help you understand the basics:

I keep hearing about “brackets.” What are people talking about? On Sunday, 68 schools were selected to participate in this year’s national tournament, based on their performances during the regular season and conference tournaments. Those 68 schools were then paired up in a tournament-style grid in which winning teams advance to play each other and losing teams are eliminated. Technically, the tournament began with two games Tuesday and two games Wednesday to narrow the field to 64 teams, and when most people talk about “THE bracket,” they are referring to that 64-slot table that can be seen here and has been the recognized format since the field expanded to 64 teams in 1985. Those 64 teams begin play Thursday and Friday, and each round cuts the field in half. The semifinalists — the “Final Four” teams — play Saturday, April 5, and the winners of those two games will play for the championship on the night of April 7.

Okay, so I can see why that’s fun for players and coaches. Why should I care and what does any of it have to do with “a pool”? A pool is basically a gambling proposition in which entrants pay a fee and, before the games begin in earnest Thursday, attempt to predict all the outcomes, advancing winners to the next line and then forecasting the winners of those hypothetical matchups until determining a champion. Your predictions on “THE bracket” thus make it “YOUR bracket.” All those entry fees are “pooled” together, and then, once the actual games are played,awarded to the most accurate prognosticator (or divided among a number of them).

That sounds illegal. Will I get arrested? Well, technically it is, but no, you probably won’t. Gambling laws vary from state to state, but anything that involves participants paying entry fees to predict the outcomes of sporting events likely violates any of them. That said, office basketball pools have become such a prevalent part of the culture that anything involving an entry fee in the $5-10 range, with a possible pot that stays in three digits, likely isn’t going to be prosecuted. There aren’t 50 million empty jail cells available.

Makes sense. But I don’t know anything about basketball. No point in entering, right? Wrong. One of the joys of the NCAA tournament for sports fans is its anything-can-happen nature; what that means for non-sports fans is that your guess is as good as any.

But I don’t even know who is supposed to be good. Help! Okay, vocab time. Take notes. Let’s start with the “seeds.” The tournament is “seeded,” meaning teams viewed as being the best play teams viewed as being the worst. The bracket is divided into four quadrants or “regions.” The 16 teams within each region are seeded 1 through 16, with the 1 seeds thought to be the strongest and the 16 seeds the weakest.

Cool, so I should just pick the No. 1 seeds to win all the time? Not so much. Of the 40 teams to make the Final Four in the past 10 years, just 14 have been No. 1 seeds. That’s more than a third of them, but far from a certainty. In fact, 2008 is the only year all four No. 1 seeds advanced all the way to the Final Four. “Upsets,” in which a lower-seeded team beats a higher-seeded opponent, happen every year. A low-seeded team that strings together several upsets is known as a “Cinderella.” If you can guess who this year’s “Cinderella” will be, you’ll have a good chance of winning your pool.

Okay, so I should just pick a lot of upsets then? Well, no, not that either. A No. 16 seed has never knocked off a No. 1, let alone won the whole tournament. While it’s fun to pick upsets and anything theoretically can happen, this hasn’t really come close since Princeton and Georgetown in 1989.

But there must be some advice you can provide? Everyone’s got a theory. Schools from the Big Ten Conference were considered overrated by some — until one of them made the Final Four four the past five years. The Atlantic Coast Conference was considered the strongest conference — but none of its schools has made the Final Four since 2010. Make of that what you will. Bracket gurus will tell you that every year a 12 seed beats a 5 seed — and in fact, the 12 seeds win in the first round 35 percent of the time — but pick the wrong 12 seed and now you have not just one game wrong, but two. If you’re feeling high-minded — or want to alleviate your guilt over gambling on the performances of 18- to 22-year-old athletes — pick based on academic performances. According to the bracket drawn up by Inside Higher Ed, which used the NCAA’s Academic Progress Rate as its deciding metric, the Final Four would be Kansas, Texas, Memphis and BYU. Or just go with the colors or nicknames you like. Everyone has a story about someone’s aunt winning their pool by basing picks on the number of people she knew who attended each school.

But, but, but … that’s madness! Exactly. Broadcaster Brent Musburger used the phrase “March Madness” to describe the constant prospect of NCAA tournament upsets. The New York Times found origins of the phrase in the description of the Illinois high school basketball tournament … in 1939.