Go Shopping! : You can cater this to all different ages. For young children, you can do a 'mock shop' and let them pretend to go shopping in a pretend store (your kitchen). Label certain items with easy to read prices and print some pretend money for them to shop with! For older children, you can let them help you in the actual grocery store with a specific shopping list. You can even set specific spending limits and give a specific amount of items and let them determine what they can afford, etc.
Children can take classes from various organizations that will support their mathematical development. These organizations may offer classes in the summer or on the weekends. Some of the classes can teach children how to build robots, toy cars, toy airplanes, etc. These classes may be in the area of engineering, computer science or some other technical field.
Elementary math is the building block on more complex topics that students must learn for the future. From simple addition and subtraction to telling time, it is a fundamental knowledge base used throughout life. Computers are also a basic fundamental building block for the future. Math programs integrate both.
Use things around the house that they already know and love! : My son has a HUGE adoration for his Thomas Trains... he can tell you every single trains name, number and color. When we started working on recognizing numbers and colors, I tried to use posters, games, workbooks, etc that would help him learn to recognize them... all to no avail! One day, we were playing with his trains, and HE asked me what number one of the trains was. Bells went off in my head and I realized that I could cater his natural curiosity about his beloved trains, and still be 'teaching' him to recognize numbers at the same time!