The book Family Math was recommended by our curriculum book and I've found it extremely useful. I've been successful thus far, teaching the kids the how-to's of math, but this book has really encouraged us to delve into math theory. It uses fun, family friendly type activities and games to encourage the learning of mathematical concepts. (I say family friendly, because the games can be tailored to all ages of learning.) There are other books in this series, as well, but I've yet to look into them yet. Check it out!