Health & Fitness: Working Out in a Personal Gym

Mark Sweeney dropped out of the health-club scene three years ago when he decided that most members spent more time socializing than sweating. "The joke was that at the club you never knew when somebody would tap you on the shoulder and ask you to dance," recalls Sweeney, 32. Rather than stop exercising, he sank $40,000 into the unfinished basement of his Rockville, Md., home. Dubbed Sweeney's Cave, it is now paneled in pale birch, carpeted in light blue and crammed with gym equipment. Among its features: a bench press, an arm-curling machine, lower-back- and leg-strengthening devices and a chest builder....