The wine country of Napa Valley has long catered to older, more conservative oenophiles. Now the spa at the eco-chic Solage Calistoga is banking on hipsters more familiar with Sideways than with Robert Parker. The 20,000-square-foot facility has 14 treatment rooms linked by lemon treelined stone paths, thermal pools, and an open-air bar where "mud tenders" customize terroir with essential oils. The Mudslide ($95) starts in a slate-tiled private room where you (and up to four friends) are left to smear warm goo on one another before baking on a heated stone slab and rinsing under rain showers. Then there's a short tub soak and a final 20-minute session in a high-tech relaxation chair that vibrates to music (massages, $115$120).