Winemaking is practiced with passion in Napa and Sonoma Valleys, an hour north of San Francisco. And in true American fashion, everybody gets in on the fun - from race car legend Mario Andretti to the former aerospace engineers who founded ZD Wines. Well-known families (Gallo and Mondavi) share the rolling vineyards with cheeky upstarts (Thumbprint Cellars). Wine tasting can be a serious education or an afternoon lark. At Sterling Vineyards, an aerial tram delivers you to the winery. Wander through cool wine caves, picnic in a gorgeous garden. Each valley has its own distinctive bouquet. Napa is the celebrity, with the attendant crowds. In Sonoma, trade a structured tour for a chat with the owner of a family-run operation. And in the event you couldn't care less about Cabernet, try the world-class river rafting, kayaking, hiking, surfing or hot-air ballooning.