It seems like this is the latest and greatest amongst yogis and those who practice alternative medicine. It's called flotation therapy and, while the video gives all the details, it's pretty much floating in what we know as a sensory depravation tank for a while. Many who suffer from tense muscles and chronic pain swear by it.
There are flotation therapy spas all over the country already. If you're in Miami and you want to try it, here's a Groupon! Let me know how it goes!