October in San Francisco has a habit of filling the calendar just when the weather starts cooperating.

If you are looking for a reason to get outside before the month ends, several of the most interesting choices do not require an admission ticket.

Start with the Sandcastle Classic.

On Saturday, October 24, the 44th annual Leap Sandcastle Classic brings elaborate sculptures to Ocean Beach near Balboa Street, with the event scheduled from 11 a.m. to 3:30 p.m.

Teams of designers, builders and schoolchildren collaborate on creations that turn the shoreline into a temporary outdoor gallery.

The event also supports arts education for Bay Area students, making it more than a pleasant beach walk.

Dress for wind, wear shoes that can handle sand and remember that the sculptures are temporary.

Follow the stories at Lit Crawl.

Also on October 24, Lit Crawl transforms Mission District businesses into a network of literary venues.

The free pop-up event brings authors and audiences together in bars, cafes, galleries and other neighborhood spaces.

Part of the appeal is wandering between readings and finding a writer you did not know you wanted to hear.

Check the organizer's current venue map because some readings have changed locations.

Step inside an artist's world.

ArtSpan's SF Open Studios continues through October 25, giving residents an opportunity to see how local artists work.

Instead of viewing finished art in a conventional gallery, visitors can explore participating studios and meet makers in a more personal setting.

Check the schedule before leaving because artists participate on different dates and at different locations.

Make a neighborhood walk the fourth outing.

A self-guided stroll through Golden Gate Park, the waterfront or the city's public stairways costs nothing and can be just as memorable as a ticketed attraction.

Choose a neighborhood you rarely visit and make the walk the destination rather than merely the route between stops.

The best free San Francisco outing may be the one that leaves room for an unexpected discovery.

Event times and access details can change, so confirm with organizers before heading out.