Boston University Summer Term has compiled a list of all summer programs offered at Boston University.
Other BU STEM programs listed here include PROMYS; U-Deign and SummerLab
The Boston Area Girls STEM Collaborative has compiled of list of STEM opportunities around Boston (some are co-ed).
Please like their FB page to learn about other opportunities as they arise.
MassTLC Education Foundation has compiled a list of after school and summer computing programs for K-12 students.
Google’s Education page lists programs and opportunities which they sponsor.