How to Save the World With 3D Printing

The first 'Tikkun Olam Make-a-thon' will bring together 230 do-gooder geeks from 10 countries. Their aim: to think up practical solutions to the problems disabled people face.

Sefi Attias is what some might call a geek. At the age of 14, he built a robot to walk behind him and schlep his books to...