Harbin Hot Springs is one of California's oldest hot springs resorts. It is operated as a non-profit retreat.
In addition to soaking in the hot springs, one can get a massage, attend workshops on a variety of topics, practice yoga and/or meditation, hike along rugged hillside trails, or just relax. Some parts of the resort are clothing-optional; no cameras are allowed there.
This is a very laid-back place. Nothing is rushed. The people here are friendly, and the scenery is pretty although not spectacular. It's out of the way, but not too far out. And the food is excellent.