Every friday evening, Gay Gaddis heads for the hills. She turns off her cell phone, sets aside the to-do lists at her Austin-based marketing firm, T3 (short for The Think Tank), and loads her five dogs into the back of her Toyota Sequoia. Then she and her husband, Lee, who is also on T3's management team, drive an hour to their 800-acre sanctuary in Burnet, Texas: the Double Heart ranch.

The couple bought the land in 1996, about seven years after Gay founded her marketing company, which now employs 140 people and has annual revenue of $43 million. On the property, they've since built a two-bedroom modern ranch house, a pool and hot tub, a skeet-shooting range, a bunkhouse with two guest bedrooms, and a half-acre vegetable garden. On a typical weekend, Gay spends hours in happy seclusion, jogging with her dogs and working in the garden.

But the Double Heart is more than a weekend retreat. It's also home to full-time ranch foreman Hardy Vaughn and a herd of 120 longhorn cattle, each named by Gay and her husband. Her favorite is 4C Princess, a brown-and-white speckled heifer with some of the largest horns in Texas--more than six feet from tip to tip. The Gaddises, who both grew up on ranches, say tending to the herd helps them feel connected to their roots.

Longhorns don't make the best beef cattle but, well, Texans love their longhorns. In the Gaddis family, they are especially treasured; Lee's family was one of seven Texas clans charged with nursing the longhorns from near extinction in the 1940s. And Gay likes their personalities. "I think they're smarter than most cows," she says. "They're very tame."

The ranch also doubles as a setting for monthly T3 gatherings and client meetings, which Lee says are especially productive--discussions unfold differently on a back porch than over e-mail. After work wraps up, the group retires to the campfire for food, some gab, and usually a bit of wine.

Despite the modern conveniences, ranch living can get gritty, and that seems to bring out the Double Heart guests' inner cowboys (or cowgirls). On one occasion, Lee and T3's controller, Mary Arnold, came across a rattlesnake while taking a walk. Lee, who was carrying a shotgun, took out the snake. Arnold jumped into the fray and severed its head and rattle with a pocketknife.

This month, Gay, Lee, and Vaughn will tackle the annual roundup. Four-year-olds are ready in January for breeding or sale at the Texas Longhorn Select Heifer Sale in Fort Worth. Beforehand, each animal will be branded, vaccinated, and weighed, and have its horns measured. A healthy animal with exceptionally long horns can go for up to $60,000. The Gaddises expect to sell 20 or 30 this year. But they don't earn a profit breeding longhorns. To help cover costs, they sell hay and artificial insemination contributions from the bulls. "We are shipping semen all over the country," says Lee.

When the roundup has come to an end and every animal is either sold or bred, the Gaddis family holds a celebratory campfire. They invite neighbors, friends, Vaughn and his family, and anyone else who happens to be visiting. Gatherings like this make the ranch worth the work. "It takes me back to the values I have and things I've learned from people out in the country," says Gay.