Take a pack of playing cards, shuffle it, and deal yourself a hand from the top of the deck. Choose whichever card game you wish. (Blackjack is preferred.)
Now look across the room and say "Let's play." If the Gambler is with you, you will feel a sudden chill on your left arm. The game has begun.
Draw the Gambler his hand and play as you normally would. For the Gambler's turn, you will lay down cards randomly from his hand.
You must never look at his hand before it is on the table. This will lead to dire consequences.
The wager of the game is your life. Should you win, you may take the top card of the deck and slice the pointer finger on your right hand. Should you draw blood, this hand will now have the power to win any gamble, provided it is used in drawing the cards, spinning the wheel, etc.
Be warned however.
Should the Gambler win, he will neither be quick nor clean about claiming his prize. And there's a reason you don't see too many people running around with lucky hands.