My first Python and PyGame project: Baby key allows toddlers to play with the computer. With each keystroke the screen gradually changes color. Holding ESC for 5 seconds allows you to quit. Windows keys and ALT+TAB combinations are suppressed as beta testing of an eight month old toddler proved this to be necessary.
WARNING: Might not be suited for your child. Beware of flashing screen (e.g. in case of Epilepsy).
Have you checked whether this might be problematic for people with Epilepsy? Make sure to warn!