I have young kids also, ages 6,5,3 and almost 2. One thing my kids love is a morning and bedtime blessing. Trace the cross on their forehead and pray for them each morning and night. Thank God for them and ask for His blessings on their day or rest. Then invite them to bless you. My kids from the age of 2 were able to pray the meal blessing, Our Father, Glory Be, and Hail Mary. I let them choose their favorite for bedtime prayers and we kneel before a crucifix in their room and pray together. I was not raised in a home that had a prayer life at all so this has all been new to me.