At least once in your life you should go down to your local American Red Cross and donate blood. My husband has done it regularly since he was in high school. That has been a lot of years. I am very squeamish about blood, especially my own, and seeing needles. But even I have donated blood.
There is always a need for blood donations not just for adults but for many children as well. There are people out there that are in desperate need of blood transfusion to keep them alive or help them survive an accident or major surgery. There are children that have to have them to survive and children should never have to suffer, they haven't had a chance to live yet.
All blood types are needed. If you have a rare type of blood, you should definitely walk yourself down to your local blood bank and donate a pint. You could and most likely will, save a life. Maybe even someone you know.
To locate an American Red Cross near you, go to this link: http://www.redcross.org