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.