Imagine showing up for a road race and a parade breaks out. Wonder Woman walks by, followed by the cast of "Gilligan's Island," followed by a giant cow who shakes your hand.

Like a scene out of "And to Think That I Saw It on Mulberry Street," the Human Race is not only the largest annual fundraiser in Sonoma County, but it's by far the biggest costume party around.

Everywhere you look there's a theme: The Living Room volunteers always haul their symbolic couch through the race, with others wearing complimentary lampshades on their heads. Kendall-Jackson Wine Estates makes the most out of wine bottles. And you can't miss the Sutter Care at Home human centipedes snaking through the race in matching outfits.

Over the past three decades, the Human Race has become a family-style, scaled-down version of San Francisco's Bay to Breakers race, without the nudity and beer kegs on wheels.

"Without the costumes I think it would be rather blah," says Jan Houts, development director for the Volunteer Center, which stages the event every year. "It would be just a form of exercise. I think the pomp and circumstance brings out the sense of Sonoma County and who we are."

Kicking off rain or shine Saturday morning, over 250 teams, 200 nonprofits and over 1,000 individuals will try to top last year's Human Race windfall of $879,000.

It's quite an achievement when you consider the first Human Race back in 1981 raised $1,800.

"We've come a long way," says Houts. "And it really has to do with everyone coming together and chipping in. It's a big party, but it's also a huge fundraiser for everyone involved."

Along with the 3k and 10k road races, the annual procession is a chance for nonprofits and businesses to bond with the community and gain exposure. Evolving from meager cardboard and stuffed-newspaper beginnings, The Living Room inflatable couch bobbing along above everyone's heads has become an annual icon.

"Every year when we walk by the KZST table, Brent Farris always calls out -- 'There goes The Living Room!' because he sees our couch," says volunteer coordinator Caroline Banuelos.

Likewise, Sutter Care at Home is known for its winding human centipedes. In 2008, around the time of the torch relay for the summer Olympics, the Sutter centipede came together as "human torches, with red troll wigs," remembers Sutter Care development officer Lucy Barnett.

This year, with the Human Race falling on Cinco de Mayo, they'll be decked out in serapes and sombreros.

"I think it all started because several of us used to go to Bay to Breakers and we sort of dreamed of getting the Human Race to be, maybe not as wild as Bay to Breakers, but to have people feel like this is something you don't want to miss," says Barnett.

Bay Area freelancer John Beck writes about entertainment for

The Press Democrat. You can

reach him at 280-8014, and follow on Twitter @becksay.