Over the years, so-called proposition betting  the sometimes absurd, usually spur-of-the-moment wagers that gamblers make among themselves  has become as ingrained as oversize designer sunglasses in the professional poker world. Huck Seed, the 1996 champion in the World Series of Poker, once bet $10,000 that he could learn to do a standing back flip in two months (he did). The pool-player-turned-poker-pro John Hennigan vowed to spend six weeks living in Des Moines, Iowa (action-starved, he returned to Las Vegas after two days). Howard Lederer, an avowed vegan, ate a hamburger to win $10,000 from a fellow poker professional, David Grey. (Offered an opportunity to win his money back by eating a few olives, which he can’t stand, Mr. Grey demurred.)

With $10,000 or $100,000 on the line, what often sound like frat-boy boasts had better ring true, and fast. “You make claims? You say you can do something? You put your money up,” Mr. Lederer said. “That is being a gambler.”

These bets offer a glimpse into the rarefied world of professional gamblers, where often money is not the object, but the pawn one moves about the board. Such wagers are “mostly a way of keeping score, but if the points are too small there is no fun in it,” said Daniel Negreanu, the winner of four World Series of Poker tournaments, who has been known to play casual rounds of Wii bowling and Golden Tee golf for sums totaling in the low five figures. “You have to understand that losing money is no big deal when you gamble for a living.”

“We don’t think of money the way that salaried people do,” continued Mr. Negreanu, who sports a goatee and two gold hoops in his left earlobe. “We don’t love money the way rich people do. We know we can always make more of it.”

Image OFF THE TABLE Daniel Negreanu, left, beat Patrik Antonius for $20,000 in a golf game. Credit... Isaac Brekken for The New York Times

His confidence is abetted by the fact that the professional poker economy has grown significantly in recent years, with an explosion of tournaments, the advent of online poker sites and promotional deals with those sites, giving top players a large pool of money to gamble with when they’re not sitting at card tables. Indicative of this is the 2008 World Series of Poker now taking place here. The event has attracted many of the game’s most successful players for a gross prize pool that is on track to exceed 2007’s total of $159.8 million. (In an unusual arrangement, the nine finalists will be chosen by July 14, but play will be suspended until Nov. 9 and 10, when ESPN will cover the final table.)