|Saint Philemon Welcoming Saint Onesimus. 14th century.|
I find bringing up the saint(s) throughout the day works well for my young children. I'll ask my daughter, "Do you remember Onesimus?" and see how much she remembers of the story. Later we might talk about how our Baptisms set us free from sin. Although Onesimus and Philemon were still slave and master, they were now brothers in Christ, united in Baptism. The Church is our family in Christ!
A fun activity for all day is to be servants to one another. Assign each family member another family member to serve, and see how they can "outdo one another in love."