Entrepreneur: David Friedberg, 28
Funding: $17 million from Index Ventures, New Enterprise Associates, Allen & Co., First Round Capital, and other private investors
Former Google (GOOG) employee David Friedberg got the idea for WeatherBill a half-decade ago, as he noticed how deeply his local bike-rental shop was dependent on good weather. In January 2007, he launched WeatherBill to sell insurance against bad weather. The online service relies on a unique prediction engine that considers weather forecasts and other data to set fees and payouts for companies as varied as a farmer in Texas plagued by drought and a golf course in Seattle that's frequently rained out. Much of the insurance is sold to big insurance companies, such as Willis (WSH) and Wells Fargo Insurance Services. Lately, travel companies have climbed on board. In 2008, Priceline.com (PCLN) began offering "sunshine guaranteed" vacations; for an extra $40, travelers can get a full refund on a trip if it's mostly rained out.
Lessons learned: "You should always have multiple deals going on," Friedberg says. "You should always have multiple partnerships available. You're never there until you're 100% there."