Fans can stop by before or during the A's 12:35 p.m. game against the Mariners, as the event takes place from 11 a.m. to 2 p.m. in the East Side Club, located beneath the center-field seats.

Fans can buy Mug Root Beer floats for $2. The floats are served by celebrities like A's greats Vida Blue and Carney Lansford, the Raiders' Tyrone Wheatley, Leeann Tweeden of Fox Sports Net, "The Bachelor" Andrew Firestone and both the Golden State Warrior Girls and the Oakland Raiderettes. One of the A's Big Three of Tim Hudson, Mark Mulder and Barry Zito will also be in attendance (although it probably won't be Mulder, since he pitches today).

All proceeds benefit the Juvenile Diabetes Research Foundation. The event has proven increasingly popular over the years.

"It started out as something small. The first year, we sold 1,000 root-beer floats," A's interactive marketing manager Cameron Stewart said. "Last year, we sold 15,000."

Thanks to "tips" given to the celebrity servers, last year netted over $36,000 for the JDRF. In addition to serving floats, the celebrities and players will be available for photographs and autographs.

And since it's Double Play Wednesday at the Coliseum, fans can buy view-level tickets for just $2 and have plenty of change left over for floats.

"Anytime the A's are able to partner with something as benevolent as the JDRF, it's a win-win situation," Stewart said. "It's amazing how efficient the JDRF is with the money they get from fundraising events."

According to the JDRF Web site, 86 percent of the organization's total expenses went towards charitable purposes. The foundation has been honored by Forbes, Barron's, SmartMoney Magazine, Charity Navigator and The American Institute of Philanthropy for its efficiency and effectiveness.

The event is sponsored by Pepsi and Comcast. Pepsi donates all the Mug Root Beer and Berkeley Farms donates all the ice cream used in making the floats.

Additional celebrities expected to attend are Nick Warnock from "The Apprentice," Danielle Reyes from "Big Brother," Dave Johnson and Shawna Mitchell from "Survivor Amazon" and members of Major League Soccer's San Jose Earthquakes.

This story was not subject to the approval of Major League Baseball or its clubs.