When Alex McEwan walked across the stage at his high school graduation, the audience went wild. Not because he was collecting his diploma, but because he was walking at all; Alex is paralyzed. But Alex wasn't cured, he was using an exoskeleton, a wearable robot that lets patients control the motion of their legs through movements in their upper body. Only catch is, you don't get to keep it. Once you've had your turn with the exoskeleton, it passes on to the next person.