Fleet Week
That sonic boom you hear echoing through San Francisco’s streets means the return of the Blue Angels for Fleet Week after a few year hiatus. The weekend kicks off with the Parade of Ships into the bay on Friday starting 11am, with Crissy Field an ideal vantage point, followed by live music at Pier 39 and airshow practice throughout the day. Events for Saturday and Sunday start at 12:30pm with the Leap Frogs parachute team, and stretch through the afternoon with ongoing airshows. Friday-Sunday, 10/10-12, San Francisco Bay.

Leap Sandcastle Contest
Indian summer is almost over, perfect time for a sandcastle building contest on Ocean Beach. Actually, it’s more sandcastle design/build, with little room for amateurs: contestants include architects, engineers, designers, contractors and local grade school students. Now in its 31st year, the theme is food, and proceeds go to a hands-on art program in area schools. Saturday, 10/11, 10:30am-4:30pm, Ocean Beach @ Balboa.

Ardenwood Harvest Festival
Both a historic and current working farm, this East Bay park is celebrating its abundant harvest with magic shows, cider pressing, old timey music and crafts. Check out the pumpkin patch and farm animals, and ride the train. Join in the corn harvest and take a bagful home. Saturday and Sunday, 10/11-12, 10am-5pm, 34600 Ardenwood Blvd, Fremont.

Columbus Day Bazaar
Who doesn’t love a parade, especially one that’s been happening every year since 1919, and in such a tradition-bound neighborhood as North Beach. The annual bazaar also serves up food and drink, face painting, pumpkin bowling, salami toss, bocce, wine raffle and music. Saturday and Sunday, 10/11-12, 10am-7pm, Sts. Peter and Paul cathedral, 660 Filbert St, SF.

Bikes to Books
San Francisco’s rich literary history is the theme for this afternoon biking tour through the city’s streets. The route circles around to all the streets named in honor of our famed authors, from Jack London Street to Jack Kerouac Alley, Rexroth to Twain. The ride finishes with a reading outside City Lights Books. Saturday, 10/11, 12:45-4pm, Jack London @ South Park Sts, SF.