Your brain likes to get into a set rhythm if it can. Get lots of exercise. Exercise is one of the best tonics we have for the brain - in children and in adults. Of course, it's good for the rest of your body, too, but it is marvelous for your brain. It helps it focus, makes it less sluggish, and gives it the food and nutrients it needs.
Exercise works wonders for a child who is grumpy, distracted, or rambunctious.
Be active with your children. Get into sports of all kinds - picking ones that you like, of course. Chase your kids around outside. This is fun and good for everyone. Some people play music well, others field ground balls effortlessly, others can take cars apart easily, others can memorize anything, and others can learn a foreign language seemingly at a glance.