GCompris

GCompris is a high quality educational software suite, including a large
number of activities for children aged 2 to 10.
Some of the activities are game orientated, but still educational.
Here is the list of activity categories with some examples:

• computer discovery: keyboard, mouse, touchscreen...
• reading: letters, words, reading practice, typing text...
• arithmetic: numbers, operations, table memory, enumeration, double entry
  table...
• science: the canal lock, the water cycle, renewable energy...
• geography: countries, regions, culture...
• games: chess, memory, align 4, hangman, tic-tac-toe...
• other: colors, shapes, Braille, learn to tell time...

Currently GCompris offers more than 150 activities, and more are being
developed. GCompris is free software, it means that you can adapt it to
your own needs, improve it, and most importantly share it with children
everywhere.
The GCompris project is hosted and developed by the KDE community.