Algodoo - Algodoo is a 2D simulator freeware product designed as a physics learning tool. It was originally created by Emil Emerfeldt as part of his master’s thesis in 2008. Read more about Algodoo.
Uxcel - The easiest way to learn UX/UI design
PhET Interactive Simulations - Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations.
UX Challenges - Done reading about UX? Start doing it.
LabsLand - LabsLand lets students access real educational laboratories through the Internet.
UI Coach - Become a better UI designer in 30 days