Here's a simple, memorable rhyming bedtime prayer for kids. If you ask me, loads better than the "if I should die before I wake" business that's been striking fear into the hearts of children for a few hundred years.
Jesus, thank you for this day.
Jesus, thank you for the way
You cared for us and kept us safe;
Gave us food and gave us play.
Jesus, thank you for your love;
And while we’re sleeping, dreaming of
Tomorrow’s fun and today’s fresh air,
Your love we breathe; Your peace we share.