Many churches in the United States organize a Day of Service in honor of Martin King Luther, Jr.'s work and message.
In addition to the ideas noted above, here are some other places at rotation.org where you will find suggestions for things that children or families can do together:
And don't miss this topic describing how you can incorporate mission and service projects into your study of Scripture passages: The "Mission" Workshop. "The key is that the chosen action or practice should come from the rotation's Bible story itself, and not be a tangential activity with a marginal connection to the assigned story." Check the article for examples.
What day of service projects has your church done? Please share them below.