Look into an Health Savings Account (HSA). Unlike a Flexible Savings Account, what you deposit can stay in there past a year and lets compound interest work for you. When you reach retirement age, you'll have a nice fund to pay for medical expenses that medicare won't pay for.
Caveat: Only suitable if you don't have any ongoing expensive medical costs (diabetes, children, etc).
Caveat: Only suitable if you don't have any ongoing expensive medical costs (diabetes, children, etc).