Fanhood is launching its sports-betting game on Facebook today as yet another new way to share the sports spectator experience with friends.

In doing so, Fanhood joins other social sports virtual-betting startups such as RocketPlay, OHK Labs (SportsPicker Challenge), Pickmoto, Bragstr, and BetHubb — all of whom have debuted in just the past month. Other rivals include, PrePlay, ESPN, Bwin, and Yahoo. All of these companies are making a big push as the fall sports season gets under way.

You could say that there is a bit of a bubble in this market, where sports fans can spend real money on virtual coins as they bet on sports. But the category is not real-money gambling since players can’t collect their winnings in cash.

Sean Ryan, the director of game partnerships at Facebook, recently concurred with us in an interview with GamesBeat that “sports fantasy apps are certainly an area that was underrepresented” on Facebook. Now more of the games are coming out in part because the social casino game market is already flooded with more than 100 games.

Most of the games are meant to create another “second screen” experience, where players can interact with the game while watching sports on TV.

San Francisco-based Fanhood features all major professional and college sports, and it offers users a gathering place to engage fellow fans through friendly wagers, challenges, pools, trivia games, and more. During its short beta period, Fanhood has gathered 40,000 registered users. Fans can interact with friends on Facebook while watching games live. The idea is to modernize fantasy sports — a $1.5 billion market enjoyed by 35 million people in the U.S. — for the social-networking generation. Users can talk openly on a forum and offer views on players, teams, or games.

“With Fanhood, we are engaging sports fans on a whole new level, making their opinions matter.” said Brandon Ramsey, the founder and chief executive of Fanhood. “As fans ourselves, we saw a distinct opportunity to create the perfect platform to make following sports with friends easier and more fun.”

Ramsey previously founded and served as head engineer at Yahoo! Shopping, Yahoo! Deals, and Yahoo! Travel. He says he has dedicated a lot of resources to infrastructure, technology development, and a “dream team” of talent that formerly worked at Yahoo, Zynga, and Slide. The company has raised capital from prominent investors First Round Capital, Mayfield Fund, and Foundation Capital. That backing is going to help the company in the race with all its rivals.

“Fanhood is providing a unique way for sports fans to engage in their passion,” said Josh Kopelman of First Round Capital. “We are thrilled to be a part of the continued growth and development of this exciting platform. This is a creative team that knows how to execute. I’m betting on them.”

As for the popularity of fantasy sports and its likely migration to social networking, Ramsey said, “Sports is a category that will happen. We’re using affinity to drive the engagement.”

As an example, if you say your favorite team is the 49ers in your social network profile, then Fanhood will search through your friend graph and find fans of the Chicago Bears — just before the two teams play each other. It will then prompt you to place a bet on which team will win.

“You can have a fun, casual experience and engage with the people you already know,” said Ramsey.

Fanhood has 12 employees and three contractors.