Physics and Software (Score 4, Informative)

Phun is an educational, entertaining and somewhat addictive piece of software for designing and exploring 2D multi-physics simulations in a cartoony fashion.

http://www.vrlab.umu.se/research/phun/

Alice is an innovative 3D programming environment that makes it easy to create an animation for telling a story, playing an interactive game, or a video to share on the web. Alice is a teaching tool for introductory computing. It uses 3D graphics and a drag-and-drop interface to facilitate a more engaging, less frustrating first programming experience.

http://www.alice.org/