Big Book Sale
Books, remember them? Those peculiar pages of paper and ink bound together in a stack that you “turn” by hand? Yes, those. There will be thousands of them in 60 categories for sale or perusal at the annual Big Book Sale at Ft. Mason’s main pavilion, sponsored by Friends of the SF Library. Friday-Sunday, 9/18-20, 10am-6pm.

Knight ‘n Ale
Wait, really? People dressed in full body armor, the type from, you know, Medieval times, whacking away at each other with swords and lances. This is not the ren faire show variety, but people who actually compete to win. Oh, and there’s beer. I feel this might just catch on. Friday, 9/18, 6:30-8pm, Westbrae Biergarten, Berkeley.

Sumo Wrestling Champions Expo
Japantown has really upped its game lately, offering attendance-worthy events seemingly every weekend. Come out this weekend and watch professional sumo with participants the size of VW bugs battling for king of the ring. Meet and greet each day at 5pm, with wrestlers such as Yama, all 6’4” and 600 pounds of him. Saturday-Sunday, 9/19-20, 12-6pm.

Silicon Valley Tour de Coop
Ride your bike around the peninsula and south bay in a self-guided tour of urban farmsteads – chicken coops, gardens, bee hives and hoop houses. Past events have featured more than 30 stops and 220 miles, while this year adds social and food events post-ride. Saturday, 9/19, 9am-4pm.

Comedy Day
Now in its 35th year, the Comedy Day in Golden Gate Park is an all-day celebration of laughter (hopefully). The extensive lineup is broken down in five sets with each comedian on stage for five minutes. Past Comedy Days have included surprise visits from comedy royalty, including Robin Williams and Dave Chappelle. Sunday, 9/20, 12-5pm, Sharon Meadow.