Audiences

These can be sought via university lectures. Typical approach:

"engineering for good University programs"
"community service" programs at universities
"college break programs"
"required community service hours"
"independent study"
"internships" programs leaders - preferably staff, professors, club leaders.
Architecture for Humanity - all will know Sketchup
Include "engineering for good programs" outside universities - such as ESW, EWB, worldwide.
Sustainability programs at universities
Open Source Engineering programs, Labs - hardware, software
Hackerspaces
Farmhack

Various Leading Orgs

Recruiting