One-off projects respond to specific situations. They don't necessarily lead to ongoing engagement, but they do facilitate the formation of leadership for mission work and provide opportunities for first-time participation.
Many congregations sent one-time mission crews to assist in disaster relief after Hurricane Katrina.
One congregation provided hall monitors for a public high school during racial unrest.
Congregations have joined special community-wide observances after tragic events like school shootings.
In these and many other instances, the congregation served overtly as a catalyst for response. This instilled pride among members and raised the congregation's visibility both among its general constituency and within the community. Members begin to think of their congregation as more than a venue for Sunday worship. That, in turn, deepens their appreciation of God and stirs their own openness to service.
The key is to have a nimble leadership system that can recognize a need, can organize a response, can provide necessary support, and trust the responders to function on their own.