PETALUMA HALLOWEEN HOUSE TOUR Visit historic parlors decorated in a Halloween theme. Costumed docents at each location will share the homes' history and lore. 6-9 p.m. $15 general, $5 for kids age 12 and under. 762-3456. www.heritagepetaluma.com.
TRUNK OR TREAT Trick-or-treating from cars, jump house, hayrides, fortune teller, haunted house, games, crafts for kids under 10. 3-5 p.m. First United Methodist Church, 2150 Giffen Ave., Santa Rosa. 545-3863.
"BOO AT THE ZOO" Entertainment, games, arts and crafts, trick-or-treating, haunted nature trail, insect zoo, haunted miniature steam train rides, costume, music, species altar. 10 a.m.-5 p.m. Free with paid admission to the zoo, $5-$11. San Francisco Zoo, Sloat Boulevard at 47th Avenue. (415) 753-7080.
"WITCHIE POO HALLOWEEN EXTRAVAGANZA MYSTERY" Witchie Poo's dress has disappeared, along with her magical powers. Musical mystery. Costumes encouraged. 2:30 p.m. $6-$9. Sebastiani Theatre, 476 First St. East, Sonoma. 996-9756.
HEALDSBURG TWILIGHT TOUR A walk down Healdsburg's vintage side streets, with tales of star-crossed romance, mystery, history and ghostly sightings. 7:30-9 p.m. $20. Adults and teenagers only, reservations required. 484-6249. www.healdsburg
HALLOWEEN AT THE LIBRARY Free. Costumes, trick-or-treating, crafts and games for ages four and up: 11 a.m. today, Rincon Valley Library, 6959 Montecito Blvd., Santa Rosa.
Scary stories for ages seven and up: 7 p.m. Monday, Windsor Library, 9291 Old Redwood Highway, Windsor.
Costumes, stories and songs for children up to age 5, 11 a.m. Tuesday, Healdsburg Library, Piper and Center streets, Healdsburg.