Years ago we decided to focus our contributions on education, particularly minority or underserved populations. We already support scholarships at 3 universities named for deceased relatives. Would probably bump the endowments by a million each. Also already support an internship program at DH alma mater that demographically has become diverse, a scientific research program at DD former all girls high school, general support at DS former high school. Would probably bump those to $250,000 each annually. Then we'd go to service teaching program at DS former college and say "what do you need....give us a proposal". Finally increase support to local organization that provides for families of children in hospital (think more comprehensive Ronald McDonald house) and local organization that provides resources to women who have been rescued out of servitude.
Edited to add: I've often had idea of community based low-income housing in group setting....possibly in under-utilized inner city school. Using help from intended tenants and community, transform each classroom into studio/ apartment. At elementary level provide housing to single parent households and at high school level to students without reliable housing. Housing would come with responsibilities....group cooking in school kitchen, cleaning and maintenance duties, childcare for parents who can work, tutoring, etc. Community services provided for basic healthcare, skills training, social services, cooking, sewing, maintenance, etc. I see a lot of synergies. Expensive to fix up and furnish the schools but would serve those communities well. Could spend a few mil on that.