Simulation Games
SimutransFree
A cross-platform simulation game where players try to successfully manage transportation systems between places by land, air, and water for passengers, mail, and goods.
The Powder ToyFree
Simulates physics interactions in a sandbox environment with various materials and elements.
ActiveWorldsFree
A sandbox platform for creating anything you can think of, inside a universe with hundreds of worlds, millions of objects, and a dedicated and friendly community.