I think the most important part is to start early. Make your kids interested in math, music, art, and sport, before they start school. Doesn't have to be anything sophisticated, simple addition and puzzles will do for math, etc. Then you have something you can later build on.

There are also ways to make things funny, including math. Most people say that they hate math, but then they do Sudoku. So, try to make more math like this. Not all math can be transformed to funny puzzles, but after a few the kids will get positive associations with the subject, and will be more willing to learn more.