The quality of these applications will vary from program to program, but most of them are really good. Here is a real short list of some of the good ones I am aware of:
- TuxTyping - A typing tutor for children starring Tux, the Linux Penguin.
- Tux Paint - A drawing program for young children, that provides a simple interface.
- LeoCAD - A CAD program that uses bricks similar to those found in many toys.
- Lincity - Build and maintain a city.