Super informal, done via Skype (I was living in NJ and this particular United Way was in SF, CA). Was asked a battery of questions to gauge skills and personality, likely to see if I was a good fit with the team I was applying to become a member of. Spoke with two people: one was a former VISTA and current member of the org in an operations role; the other was the head of the dept/team I would be working with and under, respectively.