I just came across a news story from last month about a new process that converts type A, B and AB blood to type O, so that you can turn any donated rh-negative blood into O-negative blood that can be transfused into anybody. I'm particularly happy about this because I'm O-negative, and they're always short on my type because they're giving it to everyone else (universal donor, but not a universal receiver). Not that I've ever needed a transfusion, but it's nice to know.