Flintknapping is one of the older human skills still teachable, and it's not something you stumble into at a community center. The instructor's pitch covers the full range — from entry-level arrowheads to more involved blade work — which suggests sessions calibrated to where you're starting from. No price, location, or schedule is posted yet, but the offer is 1-on-1 or small group.

If you're interested, the fastest move is to reply directly to the original Reddit thread (search r/sanfrancisco for "flintknapping") so the instructor gets a real headcount. The more responses, the faster a date and location get set. Outdoor space with a hard surface is typical for these — think a park table or a garage floor, not a kitchen counter.

If you've got two hours: reach out now, because classes like this live and die by whether the person posting gets enough replies to bother scheduling.