Ultimate Party Houses

The Japanese-born couple decided to buy the Federal-style Evermay Estate in 2011 as a base for their philanthropic work, the S&R Foundation, a nonprofit that supports individuals in the arts and sciences. Its cascading terraces, with a sweeping view of downtown D.C., are great for foundation events, they said, and the ballroom can be used to host classical-music concerts.

When they first saw the house, “we both had the feeling of immediately falling in love,” said Ms. Kuno, 59, who foundedSucampo Pharmaceuticals Inc.SCMP -0.22% in Bethesda, Md., in 1996 with her husband, Mr. Ueno, 60.

Soon afterward, the pair bought Evermay for $22 million. This year, they hosted 31 events at the mansion. Later in 2011, Ms. Kuno and Mr. Ueno also purchased Halcyon House, an equally grand Georgetown residence, for $11 million. They plan to use the property, which was built in 1787, for other Foundation activities, including a social incubator program for young entrepreneurs.

Private properties used purely for parties are a small but prestigious pocket of the real-estate market. Some homeowners, such as Ms. Kuno and Mr. Ueno, buy houses as a stage for advancing charitable causes. Others fall in love with historic homes that they rent out for events to generate income and finance the upkeep. As Americans seek more unique settings for weddings and celebrations, luxury residences for rent are in growing demand, with websites like EstateWeddingsandEvents.com and VenueReport.com devoted to unexpected and unique places for parties and events.

“In the past few years, there has been a big increase in people who want a unique place for their wedding or party,” said Jamie Ehrsam, whose EstateWeddingsandEvents.com site lists luxury homes available for rent ranging from $3,500 to $30,000 per day, depending on their location and the number of guests. “They want to get out of the hotel ballroom.”

For Washington deal makers, Hollywood celebrities and other privacy-minded hosts, private residences offer seclusion that roped-off backrooms can’t match. On Washington’s Capitol Hill, lobbyists and companies such as United Parcel Service of America Inc. and FedEx Corp. FDX +1.21% have townhouses that they use for entertaining.

Good party houses, event managers say, have an awe-inspiring, one-of-a-kind feel. Along with lots of bathrooms and ample electrical circuits to power elaborate sound systems, they also have large gathering spaces, such as a ballroom or lawn area that can accommodate numerous chairs, food stations or a tent. The most luxurious party homes often have special amenities, such as disc-jockey booths, arcade games rooms or helipads. Almost all have impressive views.

“The view is the party favor,” said Tracy Conrad, owner of O’Donnell House, a mountainside home built in 1925 by an oil man in Palm Springs, Calif., with a 180-degree view of the desert below. “You don’t need a gift bag if you can experience this view.”

Ms. Conrad and her husband bought the 4,200-square-foot, Spanish-Mediterranean home in 2000 for $1.2 million because they fell in love with its rich history. At the time, their children were small and, as Ms. Conrad recalled, “there was no way I was going to live on a mountain and worry about my kids falling over the cliff.” The couple now hosts around 40 events a year at the house, both for local nonprofits they support and for paying guests’ weddings, galas and corporate retreats. Prices vary, but the fees average about $10,000.

Outfitting a home for festivities can require an investment. Washingtonians John and Linda Quigg spent around $200,000 to turn their 107-year-old house near the city’s embassy district into an eclectic event space. The Quiggs bought the home in 1998 for $520,000, but repair and renovation costs were high, with five different water leaks in 2011 alone. So when they realized there was a shortage of intimate and unconventional party venues in Washington, the Quiggs created a small ballroom that can double as a conference space, with exposed brick walls, LED lighting and a robust sound system. In the dining room, they painted the walls silver, to reflect candlelight. An upstairs room became a boudoir with red walls and a soft fabric ceiling.

It now costs around $5,500 per day to rent Maison Biltmore, as the Quiggs have named their creation, though fees are lower for small gatherings or events for nonprofit organizations.

The owners say they aren’t making money on the events. “This is a passion,” said Ms. Quigg, 49, who manages the house full time, while her husband, 51, works as technical director at a cybersecurity company. “All goes to repairs and maintenance.”

For a holiday party hosted by Sweetgreen, a Washington-based salad chain, Ms. Quigg decked out the house in a snow theme. Large, lighted snowflakes hung in the front yard, and fireplaces carried seasonal greens with white lights and silver ribbon. The upstairs boudoir became a Middle Eastern dining room, with pillows on the floor and a low table with Turkish delight and finger food.

“For the party, we wanted an intimate space with a home feel,” said Laura Rankin, Sweetgreen’s director of special projects. “There are so many ballrooms, but that’s not who we are.”

Hosting parties has its pitfalls. At a fundraiser in 2011, a caterer left a bag of ice sitting on the floor of an upstairs room, Ms. Quigg said, which was noticed only when water dripped from the ceiling underneath. The same year, a tipsy guest couldn’t manage the old lock on the bathroom door and tried to kick it in. This summer, guests brought in a chocolate fountain for a bar mitzvah, resulting in numerous chocolate handprints on the walls.

For homes that are listed on the market, parties can double as open houses. Alex Mendez, a venture capitalist who owns Caballo Estate, an equestrian property in Los Altos Hills, Calif., said corporate events can offer especially promising exposure to potential buyers. Last summer, Mr. Mendez and his wife, Cathy, rented the estate, which has a view of the San Francisco Bay, for $5,000 to a Silicon Valley technology company for its corporate picnic. Security was so tight that guards almost didn’t let Mrs. Mendez onto the property. Mr. Mendez, whose firm focuses on information technology, and Mrs. Mendez, a pilot for nonprofit organization Angel Flight, are planning to sell the well-groomed, 11-acre estate but temporarily took it off the market because a daughter is getting married there next August.

“A party showcases the house much more than leaving it perfectly staged, as if nobody is living there,” said Roblee Valentine, a real-estate agent and owner of La Bella Vida, a resort-style home in Rancho Santa Fe, Calif., that she rents for an average of $10,000 per event.

Ms. Valentine, 52, is making what she calls a “sizable investment” in adding 3,000 square feet to the lawn area by her pool. She recently started to rent the home for parties because her kids have left and she travels a lot, but she isn’t ready to sell.

“The house is going underutilized,” she said. “I miss having people here, enjoying my house.”

Back at Washington’s Evermay estate, guests poured into the lit-up ballroom on a recent December night for a recital. An ornate holiday wreath filled the window. The Washington Monument twinkled in the distance, and a young concert artist supported by Ms. Kuno’s S&R Foundation filled the space with rich piano chords.

“This is exactly what we imagined,” said Ms. Kuno.

Write to Cecilie Rohwedder at cecilie.rohwedder@wsj.com