In the summer of 2012 I interned with Engineering Ministries International. I was 1 of 10 summer interns in their Colorado Springs, CO headquarters, and 1 of 2 architecture students. EMI can be found at emiworld.org
EMI runs on a semester schedule similar to college based on their intern availability which is a vital support for getting their work done. Each project leader has one trip per semester. While each trip has at least one staff member, the interns and trip volunteers are funded by support and are there on a volunteer basis.
My trip was ELWA hospital in Monrovia, Liberia. That project is documented here: http://architecture.michaelcporter.com/?p=88
EMI has 7 world offices and runs like a traditional A&E firm with professional oversight and reviews. They house every profession from Construction Management and Surveyors to Architects and every flavor of Engineer.
As an intern we had three methods of oversight: 1) Intern Directors 2) Project Leader and 3) a Personal Mentor. These leaders helped direct our work and grow us personally and professionally during our internship.