I'd love to donate stuff, but while I'm alive it isn't really an option. When I die my body will be donated to research. Bone marrow donation can be very invasive, but it can't hurt to sign up for a bone marrow registry. They just do a DNA swab to sign you up and then contact you if they need your bone marrow. You can decide at that time if you are in a position to be able to do it. It can be a lengthy process and can be extremely painful, but the flip side is that you can save someone's life. Lots of people who have the kind of cancer I had need bone marrow transplants to keep going. I volunteer with the bone marrow registry here sometimes. Awesome you donated blood though!