VENTURA COUNTY WEEKEND : CENTERPIECE : Bewitched and Bothered--on Dark Side of the County : Horror tours and ghost stories are scheduled for this weekend and on Halloween at ghoulish sites from Oxnard to Thousand Oaks.

On most days, with the sun shining and the blue skies patched with fluffy clouds, Ventura County can seem like the most idyllic place on Earth.

But there’s another side of the county, a spookier side, when things that go bump in the night start bumping.

Hovering ghosts, creaking walls, distant howls and other inexplicable occurrences are relatively common in this area throughout the year. Not to mention the unmentionable things that can happen during the last week of October.

Just ask the Lady in Black at Olivas Adobe in Ventura, or the playful ghost children at Heritage Square in Oxnard. Or how about the dead plumber slouched over in the bathtub with an arrow piercing his body at a store in Camarillo. Or Irving Clever and his evil twin, Skippy, who hang out at the Arts Council Center in Thousand Oaks.

While most people will go out of their way to avoid such characters, others seek them out. For the latter, here’s a sampling of horrifying Halloween happenings.

If it feels haunted, and it sounds haunted, and a psychic suggests it’s haunted, then you know what? It may be haunted.

Such is the case with the Perkins House, one of 11 Victorian-style homes-turned-office buildings that make up Heritage Square at 7th and A streets in downtown Oxnard.

“The tenants in the Perkins house now, employees of a law firm, have related quite a few unusual things,” said Gary Blum, interim events director at Heritage Square. “They hear footsteps. They see things out of the corners of their eyes, but nothing is there.”

The Perkins House and other Heritage Square homes with skeletons in their own closets will be featured in the Heritage Scare tours, from 6 to 9 p.m. Sunday through Tuesday. The tours will mix ghost stories with historical information about the houses.

Tickets to Heritage Scare are $5. Space is limited and reservations are suggested. Call 483-7960.

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Anyone who’s at all familiar with Ventura’s other-worldly side, has no doubt heard of (or seen) the Olivas Adobe’s Lady in Black, who has been sighted more times than Elvis. She was most recently spotted Aug. 6 at 9:38 p.m., following a concert at the adobe performed by the Latin jazz ensemble Nuestro.

“A worker saw her while closing up after the program. She must have liked the band,” said Ventura historian Richard Senate, known around these parts for his ghost-tracking skills. “No one knows who she is, but it is assumed that she is a member of the Olivas family.”

The Lady may be Rebecca Olivas, the last Olivas to live at the adobe. Or she may be Mother Tiadora, who had 21 children. Or, perhaps, said Senate, she could be Nellie Olivas, who died during childbirth at age 19.

Senate will share stories of the Lady in Black and about a dozen other local apparitions during the Olivas Ghost Tours on Saturday evening at the nearly 150-year-old ranch house. Mixed in with the stories will be some gentle screams and screeches suitable for the whole family.

The Olivas Ghost Tours will begin every 15 minutes between 6:30 and 8:30 p.m. Admission is $3 adults, $2 children and senior citizens. Call 658-4728 or 644-4346. The Olivas Adobe Historical Park is at 4200 Olivas Park Drive in Ventura.

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When visitors open the doors of the Camarillo Plumbing and Paint store in the old section of Camarillo, weird things happen. Spiders start crawling across the floor of the store, rats run up the walls. But in case you were thinking of shopping there, don’t worry. This kind of thing takes place only on Halloween, when the store is turned into a dark haunted house.

As might be expected at a plumbing/hardware store, when visitors enter the place, they are handed flashlights--99-cent specials--so they can safely make their way through the creepy crawlers, past the dead plumber waving at them from a bathtub, and under another dead plumber attached to the ceiling via a noose.

Store owner Kevin Nunn has been turning his store into a tame house of horrors since he opened the place in 1990. Prior to that, he owned Pleasant Valley Ace Hardware in Camarillo, which he also transformed into a haunted house each Halloween.

“It’s designed for kids. It’s not super scary. Last year we had 300 kids come through,” Nunn said, including some school groups.

Hours are 11 a.m. to 4 p.m. Admission is free. The store is at 2401 Ventura Blvd.

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If you’re looking for something on the opposite end of the terror spectrum--something that could cause sleep loss, appetite loss and perhaps loss of bodily functions--try The Haunted House Center IV at the Arts Council Center in Thousand Oaks.

About 45 members of the Young Artists Ensemble, made up of children ages 10 to 19, will split into small groups and act out bizarre, terrifying and humorous scenes in the 11 rooms of the 65-year-old structure from Friday through Sunday.

Guests will get to tiptoe from room to room, and these won’t be pretty sights. There will be torchings, murders, a rat-and-bug-cooking demonstration by the character Renfield from “Dracula,” scenes from “Frankenstein” and “The Crucible,” and a comedy-horror show.

“Half the fun and scares come from the actors of one room sneaking up and scaring the people as they go into another room,” said Scott Buchanan, the show’s producer. “It’s a theatrical haunted house. We have special effects and monsters too.”

As might be expected, the event is not recommended for young children. Evening tours of the center (which include the melodrama) will be given Friday at 7:30, 9 and 10:30; Saturday at 6, 7:30, 9 and 10:30, and Sunday at 6, 7:30 and 9.

Tickets, which are limited, are $7.50. Call 499-4355. The center is at 482 Greenmeadow Drive.