Video Poker - The Game

Game play begins by placing a bet of one or more credits, by inserting money (or in newer machines, a barcoded paper ticket with credit) into the machine, and then pressing a "Deal" button to draw cards. The player is then given an opportunity to keep or discard one or more of the cards in exchange for a new card drawn from the same virtual deck. After the draw, the machine evaluates the hand and offers a payout if the hand matches one of the winning hands in the posted pay schedule.

On a typical video poker machine, payouts start with a minimum hand of a pair of jacks. Pay tables allocate the payout for hands based partially upon how rare they are, and also based upon the total theoretical return the game operator chooses to offer.

Some machines offer progressive jackpots for the royal flush, (and sometimes for other rare hands as well), thereby spurring players to both play more coins and to play more frequently.

From Wikipedia's