[curt]

I owned a kids toy/developmental products company, be careful not to over stimulate your child. Over stimulation is just as bad as neglecting your child. This is the time to introduce your child to multiple languages, just have them playing in the background. Remember children are just large neural networks that work by recognizing patterns.

Don't focus on the subject or topic as much as the problem solving process. Children learn through pattern recognition until they have mastered language which leads to thought.

Remember children have short attention spans so only have them work on a subject/topic for a brief period or the children will develop a negative connotation with the subject.

A few people have mentioned mobile applications they are awesome. I developed a few apps that have been strongly adopted by organizations that work with developmentally challenged children. The simplicity and interactivity really makes a difference.