The recent Newsletter of the Mayo Clinic deals with the possibility of opening a health savings account (HSA).
Basically it is an account into which you can deposit tax-free money to be used for future medical expenses.
Health savings accounts were established in 2003 and are becoming more common. The goal of an HSA is to reduce the money spent on health care by placing more of the responsibility on you to shop for it. (This part is a bit fuzzy to me.)
The choice of whether to start an HSA is not an easy one, and supporters and critics have different opinions on the pros and cons, as one can read it in the Newsletter.