Having been a high school computer science teacher, I would recommend something simple. Currently, my flavor of choice would be to start with Groovy and work up to Java. Groovy's loose syntax and reduced requirements make it a natural for simple language acquisition. In addition, Groovy merges seamlessly with Java code, and most (99.9%) Java code is compilable Groovy code. As an added benefit, the Java graphics library since 1.4 has been quite simple to get up and running. There are many good books on Game Programming in Java and should work as a strong launching point. Moreover, if your child is planning on taking AP computer science in high school, the language used by ALL schools that offer AP credit is Java. And double plus good, it is very simple to move from Java to C# (indexers and delegates were really my only stumbling blocks in making the switch).