LOS ANGELES (AP) — Actor Mark Wahlberg’s Los Angeles mansion has a putting green. Tech billionaire Bill Gates’ Medina, Washington, abode includes rooms where guests can customize the music, lighting and climate. Actress Shirley MacLaine’s on-the-market New Mexico ranch includes a stone labyrinth.

Celebrity homes are a bright slice of the high-end real-estate market well beyond Hollywood. And for stars with money and imagination to spare, unique or quirky add-ons are routine. Neverland Ranch, the late Michael Jackson’s former Southern California ode to childhood — amusement park, bumper cars and all — is not alone as an example of personalized architectural opulence.

Many celebrities “are recession-proof” when it comes to conceptualizing and paying for a niftily outfitted dream home, says Santa Monica, California-based architectural designer Kevin J. Cozen, who has designed for high-profile clients for more than three decades.

For 89-year-old Hugh O’Brian, star of the 1950s and early `60s Western TV series The Life and Legend of Wyatt Earp, Cozen reduced the scale of the actor’s house in the hilly Los Angeles neighborhood of Benedict Canyon to resemble a low-slung Prairie home, with lots of wood and glass to showcase nature-filled views.

“He wanted a Western influence, so it looked like you could tie your horse outside,” says Cozen.

According to real estate expert and author Michael Corbett, who hosts Mansions and Millionaires on NBC’s Extra, quirky add-ons don’t necessarily make homes more valuable to potential buyers, especially if those quirks — say, a boxing ring, or a $70,000 wall of candy — limit the field of those interested. A celebrity name attached, though, does help.

“The rule of thumb is that celebrity homes don’t necessarily sell because they’re celebrity homes,” Corbett says. “Yet celebrities definitely increase marketability of a property. That increases the speed of the sale and sometimes the value of the property because of the marketability.”

Real-estate agent Joshua Altman, who has represented famous faces such as Kim Kardashian and stars on the Bravo TV show MillionDollarListing, is more blunt. “The property is attractive simply because of who lives there, not because of the add-ons,” he says.

Besides a putting green, Wahlberg’s 30,000-square-foot mansion, designed by celebrity architect Richard Landry and located in the gated neighborhood of Beverly Park, also features a full outdoor basketball court, a wine cellar, gym, library, and a rock-landscaped swimming pool with a waterfall and diving rock, according to TheHollywoodReporter.

Landry’s other clients include model Gisele Bundchen and her husband, New England Patriots quarterback Tom Brady, and the creator of the FullHouse TV show, Jeff Franklin.

Now on the market, Franklin’s home on a Los Angeles hillside has a master bedroom raised 40 feet in the air, with an indoor-outdoor shower. Bundchen and Brady’s French chateau-style “eco-mansion,” custom-made with sustainable elements such as a gray-water irrigation system, solar paneling and reclaimed cobblestones, was bought in June by rapper and producer Dr. Dre, the Los Angeles Times reported.

MacLaine’s New Age beliefs are embedded in every inch of her retreat near Sante Fe, Plaza Blanca Ranch, which she listed for sale earlier this year. The home includes a horse barn, chicken coop, yurt and a stone labyrinth path for meditation. There’s also an underground apartment modeled after Native American kivas, built for spiritual ceremonies, she told the Wall Street Journal in April.

Gates’ estate near Seattle is estimated by the real-estate website Zillow to be more than 50,000 square feet and worth roughly $145 million. The joint project between Bohlin Cywinski Jackson and Cutler Anderson Architects includes a 2,100-square-foot domed library with oculus, a trampoline room, a 1,500-square-foot Art Deco theater, heated floors and a 20-vehicle garage, all detailed in a 1997 overview by U.S. News&WorldReport. Visitors wear electronic pins that let a computer system track them, adjusting music, climate and lighting to each person.

The ultimate quirky celebrity home add-on could be Barbra Streisand’s. An architecture buff and collector, Streisand converted the basement of her Malibu estate into her own faux shopping mall, with a street of shops, from a doll boutique to an antique clothing store, holding her possessions.