This month’s Olympics are the first time in nearly two decades that gamblers can bet on the games in Las Vegas.

You see, back in 1998, Arizona Senator John McCain was worried about the impurity of amateur sports—which is a pretty fictional notion to begin with, but I digress—and pushed to eliminate all gambling on college and Olympic sports, not to mention such events as the Little League World Series (which actually is an event on which no one should wager anything larger than a postgame ice cream cone, and no more than two scoops).

Vegas, of course, wanted no part of that law because college sports was big business—but don’t dare pay the athletes!—and compromised: Olympic betting was out while NCAA football and basketball remained in.

Fast forward to 2015, and the Nevada Gaming Control amended state gaming rules to permit Olympic betting. Within hours, the William Hill sports book posted odds, with the U.S. men’s basketball team and host Brazil men’s soccer team as the early gold-medal favorites and the U.S. the projected leader with 6.5 more gold medals than China.

As the opening ceremony draws near, the rest of Vegas has followed suit and, while some obscure sports won’t draw betting lines due to lack of interest (and, frankly, lack of knowledge by the odds makers), the higher-profile sports like basketball, soccer, track, and swimming have pretty comprehensive offerings.

According to the William Hill odds posted on July 25, Phelps is the overwhelming favorite in the 100-meter butterfly (a $110 bet would only win $100) and a narrow leader in the 200-meter fly (6/5, ahead of Hungarian László Cseh at 7/5). Those updated odds indicate that the U.S. is an even bigger favorite for more golds: the over-under is 43.5, now 8.5 more than China’s 35.

There are also some quirky events and lesser-known athletes on the sportsbook. Despite attempting to have a well-rounded and worldly sporting interest, your correspondent regrets to say he had never heard of Anita Wlodarczyk, the Polish hammer throw record holder, until seeing that she is the single biggest favorite on the entire board. A $1,400 bet on her to win gold is needed to profit a meager $100. That’s even more prohibitive than U.S. women’s basketball.