Petaluma kicked off the 32nd annual Butter and Egg Days festival today, drawing thousands of spectators downtown for a celebration of the community's agricultural heritage.

With up to 150 entries in the parade and an assortment of musical acts, food and beverage destinations, the event is seen as the largest of its kind from San Francisco to the Oregon border.

About 30,000 people are expected to gather downtown for the all-day celebration, which closes off a roughly four-block area of the downtown from 10 a.m. to 5 p.m.

"People are ready to have fun," said Jeff Mayne of the Petaluma Downtown Association, the event's sponsor.

The day kicked off with two popular pre-parade activities, a cow chip-tossing contest and a costume contest featuring toddlers dressed up as chicks.

Petaluma City Councilman Mike Harris placed second behind fellow Councilman Chris Albertson in one of the manure-tossing divisions.

Harris, laughing about the event, said, "I can only imagine the headlines. Only in Petaluma."