Here are a few ideas to enhance your family devotions time:
Add Props - Some kids need to move to think. Consider giving your children a job to do during Family Devotions [holding the Bible, holding the notes, finding the story] or consider giving them something to hold on to that could be connected to the story [this week, perhaps a net, or some paper fish, or even a toy or paper boat].
Add Acting or Drawing - Family Devotions isn't just a task to do, it's a memory to create, a connection to be made. The more senses you can allow your children to engage the greater their memory retention. Consider drawing or acting the story as you tell it. Consider having each child help draw as you read or having each child act a part of the story.
Mixed Ages? - If you have a mix of older and younger children give your older children added responsibility. Perhaps pair them with the younger ones and have the younger repeat the verses you read after the older. Or consider having the older children take turns reading the Bible or even leading the whole time that you spend together.
Artistic or Musical? - If your children like to draw or paint, let them. Have them draw the story as you tell it and display the artwork on the wall for the week near where your Family Devotions take place. Children like to sing? Consider adding a song before or after. You might not think you can sing, but together you can all make a joyful "noise" to the Lord!