LEEUWARDEN, Netherlands - Ladies and gentlemen, start your engines — sort of. More than 20 teams from Europe and the United States are gearing up for the Nuon Solar Challenge, a contest to build and race a solar-powered boat. While a similar competition is held on land in Australia under a blazing sun, these contestants have built crafts to navigate the lakes, rivers, and creeks in the far northwest of the Netherlands, where thunderstorms are common. It would take a minor miracle for clear skies to prevail for the duration of the race, which runs from Monday to July 1....