While waiting at a traffic light with her parents in Atlanta, Georgia, Kevin and Joan Salwen's 14-year-old daughter, Hannah, saw a black Mercedes coupe on one side and a homeless man begging for food on the other. Hannah turned to her father and said, "Dad, if that man had a less nice car, that man there could have a meal."

Even as they pulled away, Hannah insisted she wanted to do something about the inequity. "What do you want to do?" her mother asked.

"Sell our house," Hannah replied.

Eventually, that's what the Salwen's did. They sold their luxurious home, donated half the proceeds to charity, and bought a modest replacement home. Though the sacrifice was great, the benefits have been greater still. A smaller house has meant a more family-friendly house. "We essentially traded stuff for togetherness and connectedness," Kevin says. "I can't figure out why everybody wouldn't want that deal."

The entire project is chronicled in an upcoming book by Kevin and his daughter, entitled The Power of Half. The aim of the book isn't to get people to sell their houses, but simply to encourage them to step off the "treadmill of accumulation"—to define themselves by what they give, and not just by what they possess. Hannah says, "For us, the house was just something we could live without. It was too big for us. Everyone has too much of something, whether it's time, talent, or treasure. Everyone does have their own half; you just have to find it."