Paul Miller couldn't quite see himself working a regular desk job. After two years of building schools and digging wells in Mali as a member of the Peace Corps, he had reservations when he accepted a position as a data analyst at Better World Books, a $45 million company that sells new and used books online. Miller was drawn to the company because it donates both books and money to organizations that support literacy -- many of them in Africa, Asia, and South America. Still, "I struggled with the fact that it didn't have that very direct, real experience that I had before," says Miller, who spends most of his days tracking metrics and forecasting revenue at Better World Books's Mishawaka, Indiana, headquarters.

But in July, Miller was back in Africa, bumping down a dirt road in a minibus, dodging cows and bicycles on the way to Gulu, a Ugandan city devastated by AIDS and civil war. There, he visited a schoolhouse being built by Invisible Children, one of several nonprofit organizations that has received donations from Better World Books. "It felt great to be out there on the ground, seeing the fruits of our work," says Miller. "I felt that direct connection again."

Twice a year, Better World Books selects eight of its 250 employees and sends them on a two-week trip to countries such as Vietnam, Brazil, Mexico, Zambia, Uganda, and South Africa. The group spends most of the trip visiting projects and people helped by Better World's nonprofit partners. The employees also squeeze in activities such as climbing Kilimanjaro in Tanzania or spending a day on the beach in Rio de Janeiro.

Unlike incentive trips -- Caribbean cruises or Vegas jaunts that are usually given as prizes to top salespeople -- these sojourns aren't meant to reward performance but rather to deepen commitment. "On a personal level, the more you are doing a job every day that doesn't directly touch the meaning and the mission of the company, the less important it becomes to you," says Better World co-founder Xavier Helgesen. "Here in the office, we aren't reading to kids. We aren't building libraries. We're trying to figure out how to collect and sell more books. Employees need a stronger connection to the mission."

But that connection is expensive: The trips run about $4,000 a person. To choose who gets to go, Helgesen and his co-founder, Christopher Fuchs, created a lottery system. Employees who have been with Better World Books at least two years qualify to enter and receive one lottery ticket for every year at the company. The longer you stay, the better your chances. Winners are drawn from a hat during a ceremony in the warehouse. One winner is typically selected from each department, though a few of the smaller divisions are grouped together so that everyone gets a fair shot. "Many have never had a passport before, so this can be a life-changing experience," says Helgesen.

The lottery idea was the culmination of several years of experimentation. When the founders started the travel program, in 2006, they recognized they couldn't foot the bill for companywide trips, no matter how much they wanted to. At first, Helgesen and Fuchs tried using performance targets to determine who would go. That made sense for the sales department. But they wanted employees from every part of the company to share the experience. "So could the top-performing accountant go?" says Helgesen. "The top-performing book shipper? You run into a dead end that way. You start out trying to do something nice, and it turns into a human resources boondoggle."

The founders had also toyed with the idea of offering the trips to more people by asking employees to pay part of the expenses -- up to 75 percent in some cases. But that resulted in complicated formulas for calculating subsidies -- coupled with the potential perception of unfairness -- and skewed participation toward employees without families. In 2008, Helgesen and Fuchs decided to pay for the whole thing.

Helgesen says turnover is down by half since the company instituted the trips. Although he attributes that decline to a number of factors, including the introduction of stock options, the travel program is exactly the kind of perk that entices idealistic Millennials like Mary Olson, who is the manager of one of Better World's two retail outlets. Olson, who recently became eligible for the lottery, is so excited by the prospect of visiting Africa that last year she tattooed the inside of her right wrist with a heart incorporating the outline of the continent. "I've never been there, but I've always felt like it's a part of me," says Olson, 29.

Although participation in the travel program is limited, it has a ripple effect, says Helgesen. "When employees come back, they evangelize about what they have seen," he says. That's what products manager Paul Drake did after returning from the same tour of about 20 African schools and libraries that Miller went on. Drake told all his co-workers about Agnes, an African girl who is a junior in high school and has promised her mother she is going to be a doctor. "I saw our books in her school," he says. "It made it very real to me."