Chess and Mahjong

Fri · Oct 30·2 PM·United Nations Plaza, 50 United Nations Plaza, San Francisco

Free chess and mahjong lessons and play at United Nations Plaza.

Fri · Oct 23·Presidio of San Francisco. Specific meeting location will be listed in the registration confirmation email.

Volunteer planting, weeding, and mulching young trees in the Presidio’s reforestation areas while learning urban forestry and arboriculture.

Fri · Oct 23·3601 Lyon St, San Francisco

Cal Hacks 13.0 (3601 Lyon St, San Francisco) — 36‑hour hackathon offering workshops, industry mentors, corporate partners, food, swag, and prize pool of cash and devices.

Fri · Oct 23·5 AM·Event Location, San Francisco

Cycle track open before 2:00 PM at Event Location, San Francisco.

Fri · Oct 23·8:30 AM – 4:30 PM·San Francisco, CA (Farallon Islands)

Eight‑hour naturalist‑led whale watching expedition sails from San Francisco under the Golden Gate Bridge to the Farallon Islands, featuring an expert naturalist, $320 per person, ages 13+.

Fri · Oct 23·4:30 PM·Golden Gate Bandshell, Music Concourse Drive, San Francisco

Friday Happy Hour at Golden Gate Bandshell, Music Concourse Drive, San Francisco.

Fri · Oct 23·6:45 PM·Event Location, San Francisco

Cycle track open after 6:45 PM at Event Location, San Francisco.

Sat · Oct 24·5 AM·Event Location, San Francisco

Cycle track open until 7:30 AM at Event Location, San Francisco.

Sat · Oct 24·10 AM·Rochambeau Playground, 238 25th Avenue, San Francisco

Mobile Rec at Rochambeau Playground, 238 25th Avenue, San Francisco.