LOUISVILLE, Ky. -- The Kentucky Derby is Saturday at Churchill Downs. Here are five things you should know before the 6:24 p.m. post time:

DOUG'S DOUBLE

Doug O'Neill is back at Churchill Downs trying to win his second straight Derby. He put unknown Mario Gutierrez on I'll Have Another last year and they won. This time, he's got another relative unknown, black jockey Kevin Krigger, aboard Goldencents. No trainer since Bob Baffert in 1997-98 has won two in a row.

DERBY TRADITIONS

If you're at Churchill Downs on the first Saturday in May, tradition calls for a mint julep in your hand and a fancy or outrageous hat on your head. Consumed early and often, the juleps are served over crushed ice in souvenir Derby glasses. Bigger and bolder is the rule for hats that often dwarf their owners. And don't forget some cash to push through the betting windows.

BO-RAIL

No jockey's been hotter in the Derby than Calvin Borel, having won three of the last six. He's aboard Revolutionary for the first time, one of five horses in the race trained by Todd Pletcher. Look for him to live up to his "Bo-rail" nickname with a rail-skimming ride.

ON A ROLL

Verrazano is the only unbeaten runner in the 19-horse field. In the last decade, three undefeated horses kept their records intact by winning the Derby – Smarty Jones, Barbaro and Big Brown. Verrazano didn't run as a 2-year-old, a bad omen. No horse since Apollo in 1882 has won without racing as a juvenile. Verrazano is named for the bridge that links Brooklyn with Staten Island in New York City.

BACK IN THE SADDLE

Injuries weren't going to keep John Velazquez (http://bit.ly/16A60V2) from riding undefeated Verrazano in the Kentucky Derby. The jockey busted a rib and his wrist in a racing accident nearly a month ago. He hustled back two days ago and rode a handful of races in preparation for the big day.

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    LOUISVILLE, KY - MAY 04: Miss Kentucky USA Whittney Allen celebrates the 139th Kentucky Derby with Moet & Chandon at Churchill Downs on May 4, 2013 in Louisville, Kentucky. (Photo by Mike Coppola/Getty Images for Moet & Chandon)

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    LOUISVILLE, KY - MAY 04: Race fans wearing festive hats attend the 139th running of the Kentucky Derby at Churchill Downs on May 4, 2013 in Louisville, Kentucky. (Photo by Jamey Price/Getty Images)

  • James Cowherd, center, from Las Vegas, Nev., poses for photos with other spectators before the running of the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • A spectator slides on a rain soaked tarp before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • A spectator arrives with her fancy hat to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • From left, Amanda Dugan, Bernadette Osborne and Tracy Clay watch the fourth race before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • Spectators wait in the rain for the next race during the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • From left, Donna Osborne, from Clemens, N.C., waits in the rain with Annie and Oz before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • Race goers take cover from rain under their jackets before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Charlie Riedel)

  • Race goers walk through water puddles before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Charlie Riedel)

  • Former NFL player Warren Moon arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Jennifer Tilly poses as she arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Carolina Panthers head coach Ron Rivera arrives with his wife Stephanie to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Country singer Luke Bryan arrives with his wife Caroline to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Retired NBA player Scot Pollard arrives with a friend to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Louisville head basketball Rick Pitino and his wife, Joanne, arrives with a guest to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Former NFL player Tikki Barber arrives with his wife Ginny to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Desirae Masterson, de Indianápolis, Indiana, con su sombrero cubierto por una bolsa de plástico para protegerlo de la lluvia, comparte un julepe de menta con su esposo Ray antes del 139vo Derby de Kentucky en Churchill Downs, el sábado 4 de mayo de 2013, en Louisville, Kentucky. (Foto AP/David Goldman)

  • Willy Weaver, from Albany, Ga., walks through the paddock area before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • Comedian Garrett Morris arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Actress Kyrsten Ritter arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Race goers take cover from rain under their jackets before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Charlie Riedel)

  • A spectator protects her fancy hat from the rain before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • Brenda Williams, from Tulsa, Okla, waits in the rain for the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)

  • A spectator arrives with her fancy hat during the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • A spectator arrives with her fancy hat to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • A spectator arrives with her fancy hat to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • A spectator arrives with her fancy hat to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • A spectator arrives with her fancy hat to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • Spectators arrive with fancy hats to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • Miss American 2013 Mallory Hagan arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Model and television personality Bonnie Jill Laflin arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • A spectator drinks chapagne with her fancy hat during the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • Model Coco Rocha arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Miss American 2013 Mallory Hagan arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • A spectator arrives with her fancy hat during the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Matt Slocum)

  • Former NBA player Scottie Pippen arrives with his wife Larsa to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Country singer Miranda Lambert arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Former NBA player Julius "Dr. J" Irving arrives with his wife Dorys to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Actress Jane Seymour arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Author Nora Roberts arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • "Ready For Love" actress Angela Zatopek arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Former NBA player and coach Avery Johnson arrives with his wife Cassandra to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Country singer Miranda Lambert arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • "Storage Wars" starts Matt and Mark Harris, left, arrive to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • US skier Bode Miller and his wife Morgan arrive to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Former professional baseball player Ken Griffey Jr. arrives with his wife Melissa to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • Former professional baseball player Ken Griffey Jr. arrives to attend the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Darron Cummings)

  • A spectator walks through the paddock area in the rain before the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/Charlie Riedel)