When he was just 19, Denver resident Brad Ludden became Nike’s first sponsored kayaker. That same year, 2001, he founded a nonprofit called First Descents to offer a free kayaking camp as therapy for young adults fighting cancer. More than a decade later, First Descents employs 13 people, three interns, and 22 contract workers at its Denver office, and will run nearly 50 camps this year, including white-water kayaking and rock climbing. “I could never have anticipated it,” says Ludden, whose aunt battled cancer. What’s more, Ludden, 31, has grown the company using the “pay-it-forward” business model. The idea is simple: Participants—cancer survivors and patients between the ages of 18 and 39—can attend a one-week camp for free but are encouraged to donate at least $1 to First Descents, paying it forward for future participants. A dollar may not seem like much, but last year camp alumni, board members, and supporters—674 individuals, some of whom gave much more than a dollar—raised $850,000. Help First Descents by donating money, hosting a fund-raiser, or volunteering at a camp. firstdescents.org