One of the things that I think is absolutely amazing in the world right now is the different ways that people are using 3D printing to produce prosthetic limbs for people who couldn't otherwise afford them.
I saw in the newspaper the other day that a high school technology class took on a project where they designed (with the help of experts) and printed out a limb for a two year old who needed one and couldn't afford one. According to the little girl, the best thing was, she got to choose the color and it was very light, so it worked well for her.
I remember when I was a kid, we had a girl with only one natural leg and her previous artificial limbs were kept in the staff room. Kids grow out of their prosthetic limbs quickly, so a cheap way to replace them, made to order, is a fantastic thing.