And they're off! Roughly 20 of the finest, fastest horses in the world will charge out of the starting gates this Saturday during the 140th running of the Kentucky Derby. At Churchill Downs alone, eager bettors wager more than $100 million on their favorite ponies.

But you don't have to attend the race to get in on the action. Off-track betting (OTB) sites across the country, and other gambling sites or casinos, allow you to legally lay a few bucks on your favorite horse. Here, an expert analysis of everything you need to know about wagering on this famous horse race.

The Names

Racehorses' names can seem crazy or nonsensical, but there's usually logic behind each one, says Jill Byrne, a racing analyst and official handicapper for Churchill Downs. A lot of owners name a horse for its parents. An example from this year's Derby: Intense Holiday is the offspring of Harlan's Holiday (the father) and Intensify (the mother). Owners also choose names with personal meanings. The 2012 Kentucky Derby winner, I'll Have Another, got his name because his owner would always say to his wife, "I'll have another" when asked if he wanted more of her fresh-baked cookies. [Tweet this fact!]

The Favorites

Every horse in the Derby has either won similar events or runs extremely well competitively, so any of these beauties could win, says Byrne. But there's definitely a favorite: California Chrome. "He's won his last three races as easy as can be," Byrne says. Intense Holiday and Hoppertunity are two others she believes could finish near the front of the pack.

The Underdogs

Wicked Strong just won a big race called the Wood Memorial, and is well suited for the track distance in Kentucky, Byrne says. Another horse she mentions as a "hot" longshot bet is Danza. If you're only planning to wager a dollar or two, and want the chance to win $15 or $20, these underdogs (under-horses?) may be worth betting on.

The Odds

When visiting an OTB or casino to bet, you'll see figures like "3-to-1" or "25-to-1" assigned to each horse-the amount you'll win for a $2 bet, Byrne explains. To calculate your potential winnings, divide the first number by the second and multiply it by the amount of your bet. For example, if you bet $2 on a horse with 8-to-1 odds, your potential winnings would be $16. (8 / 1 x 2 = 16.) Remember, odds shift until the race's start.

The Wagers

An "across the board" wager on a single horse means he could finish in first, second, or third (also known as "win, place, or show") and you'll win your bet, Byrne says. (She uses "he" because there are no female horses running in the Derby this year!) You won't win very much money picking a favorite like California Chrome "across the board," but the odds are pretty strong that you'll win something.

The Riskier Bets (for Larger Payouts)

A trifecta wager requires you to pick the first, second, and third place finishers in the correct order. "That's tough to do," Byrne promises. But if you're right, a $2 wager will likely win you $100 or more, she says. The exact amount of your winnings depends on the odds for each horse. If all three were underdogs, you'll win much more than if all three were favorites.