Kentucky Derby: Eight things to know for the 138th Run for the Roses at Churchill Downs

(CBS News) With the first Saturday in May approaching at a steady trot, it's time for sports fans who only tune in to horse racing for the Triple Crown (this journalist included) to once again focus their attention toward the famous twin spires in Louisville, Ky., for the Kentucky Derby.

Before pulling your Derby hat or seersucker suit out of the closet for a viewing party Saturday, check out our handy cheat sheet to make some small talk about the 138th Run for the Roses.

Kentucky Derby: Bodemeister is early 4-1 favorite
Night racing a hit, but not yet for Kentucky Derby
Kentucky Derby a rematch for top contenders

Who's the favorite to win?: Bodemeister was the odds-on favorite (4-1) in Thursday's morning line. Many experts chose other horses as their winning pick, notably Union Rags, whose 9-2 odds were just nosed out by Bodemeister. The odds will change constantly until just before the race. It's worth noting that Animal Kingdom won last year's Derby at 20-1 odds, and Super Saver crossed the finish line first in the 2010 Derby at 8-1 odds.

How many horses are in the race?: As of this writing, a field of 20 horses have been assigned post positions out of 21 entrants. Scratches aren't unheard of though. Should one occur, My Adonis is waiting in the wings to fill the empty starting gate.

When does the race start?: Post time is 6:24 p.m. ET. The race should start soon after that.

What's the weather forecast?: Not ideal. According to the National Weather Service, the forecast for Louisville calls for scattered showers and thunderstorms with a 40 percent chance of precipitation during the day, improving to isolated showers and thunderstorms with a 20 percent chance of rain at night. Two years ago, a bad forecast prompted Churchill Downs to consider running the Derby under then-newly installed lights for the first time in its history.

Who's singing the national anthem?: Mary J. Blige is expected to sing the anthem around 5:10 p.m. ET after the last race before the Derby, the Woodford Reserve Turf Classic.

What's that other song played?: Stephen Foster's "My Old Kentucky Home" is traditionally played by the University of Louisville Cardinal Marching Band as the horses are led to the starting gate. Scroll down for lyrics.

What's in a mint julep?: The traditional Derby drink contains bourbon, mint and simple syrup plus some other ingredients depending on the recipe. Click below for recipes from the CBSNews.com archives.

Bobby Flay's mint julep
It's derby time: How to make mint juleps

Who was the last horse to win the Triple Crown?: In 1978, Affirmed was the last horse crowned with victories from the Kentucky Derby, the Preakness Stakes in Baltimore and the Belmont Stakes in New York. In 2008, Big Brown came close to winning the crown, entering the Belmont with wins from the previous two legs, but he lost to Da' Tara.

"My Old Kentucky Home" lyrics

The sun shines bright in the old Kentucky home,
Tis summer, the people are gay;
The corn-top's ripe and the meadow's in the bloom
While the birds make music all the day.

The young folks roll on the little cabin floor
All merry, all happy and bright;
By'n by hard times comes a knocking at the door
Then my old Kentucky home, Good-night!

Weep no more my lady. Oh! Weep no more today!
We will sing one song for my old Kentucky home
For the old Kentucky home, far away.

Source: Churchill Downs Inc.