Level Playing Field Institute
This Bay Area organization is committed to eliminating the barriers faced by underrepresented people of color in STEM and fostering their untapped talent. You can find more information at http://www.lpfi.org/programs.
code.org is a global organization with a goal of teaching as many kids as possible STEM in K-12 education. They offer online tutorials, provide templates to request CS classes at schools, have tutoring/classes after school, and arrange for software developers to volunteer to help out with these. Go to http://code.org/ to find many ways and opportunities to give back.
Generation Stem Inc
This Atlanta-Metro area charity puts on hands-on workshops and projects for children aged 4-14. $137 covers a scholarship for 1 child. You can get more information at https://www.engineeringforkids.com/metroatlanta.
Silicon Valley Education Foundation
SVE Foundation provides advocacy, programs and resources to help students reach their full potential in the critical areas of STEM. Their programs target students and teachers in the Bay Area, and include summer camps, scholarships and teacher grants. Find out more at http://svefoundation.org/.