A sort of Burning Man meets Cannonball Run, the Great Arcata to Ferndale Cross-Country Kinetic Grand Championship draws more than 10,000 spectators who come to watch crazy competitors try to slog through 38 grueling miles of sand, swamp, and salt water in their custom-made, people-powered amphibious crafts. www.kineticgrandchampionship.com

Ranked 7th among the top 10 food festivals in the world by Away.com, the Arcata Oyster Festival has become a tradition for local restaurateurs to show off their culinary skills by preparing oysters in every imaginable way. Over 70% of the fresh oysters consumed in California are grown in 450 acres of Arcata Bay where the conditions are ideal. Crowds throughout the day top 15,000 to 18,000, keeping local food vendors more than busy. Highlights include local craft beer and wine, the "World Famous Oyster Calling Contest", live entertainment, and activities for kids. www.redwoods.info

The hillside trails of Prairie Creek Redwood State Park have exceptionally thick concentrations of wild Pacific rhododendrons, and now is the peak time to see them in bloom. The two-mile Rhododendron Trail, just north of the Visitors Center, is one of the best place in California photograph the bright, rounded clusters of large, tubular flowers and soft, leathery, deep green leaves. www.redwoods.info

One of the top community festivals in the nation! On Saturday & Sunday, June 1 & 2, Heather Farm Park in Walnut Creek will sizzle with the sights, sounds, and flavors of the best Bay Area artisans, musicians, winemakers, festival foods, and the zany Grape Stomp Competition, kicking off summer fun under Walnut Creek’s sunny skies. More than 90,000 attendees are expected over the weekend, and admission is FREE!