Some have a time limit to complete tasks, much like a game. If the math problems are not completed in time, a buzzer sounds indicating that they are out of time. This raises the competitive level from simply completing tasks to competing for how quickly they can do it, and do it correctly.
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!
The classes can be taught at the various colleges or universities in the local area. This is a community outreach for the colleges and universities, but children will develop social and academic skills that will carry over to their classroom and on to adulthood.
Get in the Kitchen! I was very hesitant for a while with my son when it came to the kitchen. I worried about the GIANT mess that would be left when he was done "helping". You don't even have to take on the entire project with them! You can start small and let your child help with measuring certain ingredients. You can modify the difficulty of the 'lesson' by talking about the different kinds of measuring cups and seeing what other measurements can also add up to equal one cup, etc.