I gave a suggestion to one of our older students about taking a weekly Parami to work with, for example developing the Parami of generosity and reflecting, "How am I going to generous?" so that you can think of specific things in your life that will enable you to practice generosity. To cover all the Paramis it will take ten weeks. If you do that on your own, as a parent, you might want to include your children if they are interested. Give them a teaching about good, healing qualities and how, "I am going to try to be as generous as I can for this whole week. Do you want to join in?" If you are doing it together it may seem fun - if you expect the child to be generous but don't try yourself there may be resistance! The best teaching is being an example, how you're attempting to to be generous, learning to be moral, etc. That could be be interesting.
Certainly the more you think about how you can develop the Paramis in your life, week by week, the more inspiration you will get on how you can teach these to your children as well. Because unless you know how to develop them yourself, and see opportunities in your normal life to develop them, how can you teach it to your children? First of all, being an example and role model to your children is very helpful. Since ten weeks may be a bit long for children to keep the inspiration going, maybe try doing this for ten days and see what you have learned from those ten days yourself and see how you can actually help the children join in.
There was a time where I was trying to teach children about compassion and I took them into the forest and tried to get them to imagine themselves as little creatures. Children have a very vivid imagination, so they were quite able to do this. These are opportunities to help them develop compassion, for them to imagine themselves as the ants, etc. and the life these small creatures have.