(FORTUNE Small Business) – • Addison Pemberton | Vintage planes

He seems a well-grounded person until you learn how Addison Pemberton spends his free time. Pemberton, 51, runs Spokane-based Scanivalve, a maker of high-tech pressure and temperature gauges that he took over from his father. Every afternoon at five, however, he heads to the hangar that houses his collection of vintage aircraft. Pemberton has restored 19 such planes--he now owns six--and has logged some 10,000 hours of flight time. His favorite is the 1931 Stearman 4DM Sr. Speedmail biplane shown here, one of only five in the world, which he takes out for half-hour hops most days. "You feel the wind in your face," he says. "It's a trip back in time."

• Marjorie Bekaert Thomas | Polo ponies

Thomas, 58, is so devoted to Polo that she leaves her home in Winter Park, Fla., every summer and heads 3,700 miles northwest just to play with the Calgary Polo Club, considered North America's best. She and her husband, Bryan, who also plays Polo, bring their 12 thoroughbred horses (driven up in a trailer by the groom and his family) and four dogs. "I call it a work-cation," says Thomas. "I work anywhere from two to five hours in the morning before going out and playing in the afternoon, six days a week." She also returns to Winter Park for one week each month to manage Ivanhoe, a 15-employee company that produces syndicated medical-news segments for TV broadcasters. Thomas co-founded it with a friend, Bette BonFleur, in 1982. During the sport's spring season she drives two hours each way every weekend to play with the Sarasota Polo Club. Although she considers herself "quite a few notches below professional," Thomas has played on winning teams in regional tournaments. Her description of the sport? "Hockey on horseback, played with the elegance of dance."

• Justin Aldi and Ronnie Da Motta Antique cars and trucks

As a kid, you always want a fire truck," says Justin Aldi (right), who now owns one with Ronnie Da Motta, his best friend and co-founder of First Security Lending, a Burbank, Calif., mortgage bank they launched from Aldi's living room. First Security has 175 employees and $14 million in annual revenue, and it will handle nearly $800 million in loans in 2005. Aldi, 30, and Da Motta, 31, bought the fire engine three years ago for $10,000--an anniversary series edition that had spent most of its life in Mason, Iowa. It's the highlight of their jointly owned collection of 30 classic cars and trucks, including a 1927 Texaco truck and a 1966 Triumph TR4. Restoring the fire engine cost them another $20,000, thanks to period-perfect accessories such as a Roto Ray light--a warning signal used on certain trucks in the 1940s. "It's hard to find them intact, but after a three-year hunt on eBay, we got one," Aldi says.

• Mario Russo | Modern art

Most hair stylists consider themselves artists. But Mario Russo, who owns two popular eponymous salons in Boston and a line of hair- and skin-care products sold in department stores, is an art collector as well. Over the past 20 years he has bought more than 150 minimalist and conceptualist paintings, sculptures, and photographs. Most weekends (and during the occasional lunch hour when he can get away), he visits galleries and meets with art dealers. He takes vacations during Art Basel, a major show for collectors held every year in Switzerland. The untitled Sol Lewitt work above was painted in 1991, and Russo bought it a year later after seeing it at Boston's Museum of Fine Arts. Lewitt is a dominant figure among contemporary U.S. artists and a renowned sculptor--he recently created works for the sculpture garden of the Metropolitan Museum of Art in New York City, on display there through the end of this month. Russo splits his collection among his salons and his three homes (in Boston, Cape Cod, and Woodstock, Vt.). "I'm long out of wall space, but I keep purchasing," he says.