First, I asked him to succinctly describe the mission and objective of his non-profit.
Second, I asked him to define his roles and responsibilities as executive director and the roles and responsibilities of his board of directions.
Then third, I asked him to within the context of the first two items, define the types of ways he wants volunteers to assist. What kinds of things does he want them to do?
Fourth, I asked him to look through the resume information submitted by the volunteers to understand their particular gifts and talents, and how they match up with the tasks he wants assistance with.
Then I asked him to match smaller subsets of the 24 volunteers and their talents with the tasks he wants done.
Now this executive director has a half a dozen small teams of volunteers working enthusiastically and productively on specific tasks he asked them each to do, and they are all making significant task contributions to the non-profit and are all enthused about how they are helping. And once a month we get all the small groups together to share in the contributions we are each making to the non-profit.
Bottom line – the way to most productively engage volunteers is to know what you need done in light of your mission and what other responsibilities are already assigned, match the needs you have to the background and talents of the volunteers, and then ask them do specific meaty projects that match their desires and talents.