Impenetrable rainforests, palm-studded beaches--Hawaii has many stirring sights. But for Jason Earle, the putrid, mold-ridden Hilton Hawaiian Village's Kalia Tower in Waikiki was most inspiring.

In 2002, during a sojourn to the Aloha State after he ditched a nine-year career as a stockbroker, he watched as the $95 million hotel was closed down one year after opening because of ventilation problems. "They thought it was a $500,000 mold problem, then it grew to $5 million," he says. "In the end, it cost $55 million to fix." From Entreprenuer.