I've been hearing more and more about the benefits of float therapy. Yes, it's exactly what it sounds like. You tuck yourself right into a "sensory deprivation tank", aka a floatation tank, and float in water mixed with epsom salt for 30 minutes to an hour. The purpose is to induce complete relaxation which in turn reduces anxiety, stimulates creativity, relieves pain, increases focus, etc.
There are a number of wellness centers in the Boston area that offer tanks. Here are the ones I can find, one of which I will hopefully have the opportunity to try soon: