Simple and fun paint program for young children

Tux Paint is a free, award-winning drawing program designed for young
children aged 3 and up. It has a simple, easy-to-use interface with
fun sound effects and an encouraging cartoon mascot.
Features include paintbrushes, stamps with hundreds of images,
special effects, text tool, undo/redo, and the ability to print artwork.
Available in over 100 languages.