GCompris (http://www.gcompris.net/index-en.html): more than 140 educational activities from 2 to 10 [en].
PhET (http://phet.colorado.edu/); Interactive simulations for science and math : now in HTML5 (http://phet.colorado.edu/en/simulations/category/new) [en].
PrimTux (http://primtux.fr/): educative distribution officially recognized by Debian (https://wiki.debian.org/Derivatives/Census/PrimTux) [en].
Scratch (https://scratch.mit.edu/): Program games, animations and interactive stories [en].
Sugarizer (http://sugarizer.org/): A taste of OLPC-Sugar on any device [en].
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