Teach Them to Your Children by Sarah Wean is a book with one-page stories related to character formation, such as obedience, kindness, forgiveness, trusting in God, etc. Each story contains a short poem, illustration and scripture verse to go with it. We've read this book off and on for a few years, and the kids really like the stories. So I've been using this book to reiterate the virtue we are discussing. We follow this with their favorite part...skits. They love to act out scenes.
Now I don't plan to do a devotional everyday nor do I plan to always use the same formula (book, skits, etc.). Whatever works for where they are at at the given moment. For example, Chap spent the last month reading with them through the old testament about Joseph and his response to suffering the right way. He was trying to teach them how to respond when things don't go their way. We normally do all of this as a family in the evening, but I am compelled to do more during the day when they are with just me. I have come to the realization that it takes a life time to develop good virtues and character. So if they don't get it now, they'll have plenty of opportunities in the future.