The best way to run gambling for the Kentucky Derby is make an exacta board. You have the win line across the top and the show line down on the left side. Since there are 20 horses you will have 380 boxes (20 x 19). $2 per bet. However, you do need rules. Below are the rules that I use:
KENTUCKY DERBY 2010
EXACTA WAGERING
Simply select the 1<SUP>st</SUP> and 2<SUP>nd</SUP> Place horses in the correct order of finish and win all the prize money collected. In the event there is more than 1 winner, the prize money will be split evenly among the winners.
All bets are action in the event of a scratch.
$2.00 per bet.
In the event that there is no winner, the prize money will be split evenly among everyone that selected the winning horse as the first horse in their exacta. In the further event that no one selects the winning horse in an exacta, the prize money will be split among everyone that selected the place horse as their second horse in their exacta.
Need not be present to win.
GOOD LUCK EVERYONE!.