I volunteer with the organization Organizing for Neighborhood Equity – DC (ONE DC). They accept interns on a rotating basis. I think this fits within the broad definition of social justice, community organizing, and urban policy work. Here is the description: https://www.onedconline.org/internships
I would be happy to talk with students who may be interested in this organization and position. I might recommend that interested students attend an online meeting to learn more about ONE-DC before applying; they have a specific set of anti-racist movement principles that they uphold.
I will try to think of other possible opportunities. I don’t have any myself right now, but might in future summers.
My family might also be able to host a summer home stay by students who do an internship in the DC area — with ONE DC or any other group. We live in DC and have just renovated our basement to accommodate visitors. I can provide more details if there is interest.