After most wins in Video Poker a player is offered the chance to gamble with their winnings. They can choose to try and Double-Up their wins or at least gamble half of their win. These bets are a straight 50/50 wager.
Always bear in mind that you are risking your hard-won gains when you choose to gamble with the Double-Up option. It's great if you win but you're going to be feeling very sorry for yourself if you lose!