Watsu Therapy
The MorningPaper has an article on something called Watsu®. The term is a combination of water and shiatsu massage. As you might imagine, the therapy is done in a pool and is said to provide temporary relief to all manner of afflictions.
I have no idea if any of these statements are true nor do I think it is a cure for what ails you, but I could think of worse ways of getting a massage. Maybe the next time I'm on the Big Island or Kaua'i I'll look into one of these. YMMV. Insert disclaimer here.
Aloha!