One of the coolest organizations I've had the chance to work with is E-nabling the Future. They work with engineers, designers, and 3d-printing hobbiests to provide low-cost prosthetic arms for anyone who needs them. At the Rehabiliation and Neuromuscular (ReNeu) Robotics Lab, I met Maddie, who had a recent amputation and was interested in 3d-printing a temporary replacement. In just 2 weeks, a labmate and I customized, printed, and assembled an E-Nable design that Maddie could use to help with daily activities. Now she has a state-of-the-art robotic hand, but the 3d-printed version helped for 4 months or so before she could get that.