What about this
gift registry idea??
The couple, "Sarah and Kiril Lozanov used their wedding registry blog to educate friends and family about solar energy, and included a solar panel fund to purchase solar for their Chicago-area condominium in their gift registry."
They educated guests on solar energy and the plan for their home and with gifts from wedding guests and Illinois solar tax breaks and a tax credit brought them about 50% closer to their goal.
Plus lots of people learned about solar energy in the process!