Golems Universal Constructor is a highly addictive 3D physics and artificial intelligence simulator. It is cross-platform and written in Java. It is currently in open-beta and the developers are always looking for new testers. The easy-to-use interface allows you to build simple or complex designs which react to newtonian physics. Joints, motors and sensors can be wired together to create machines that become self-aware or responsive to human input. There are several Golems demonstration videos on YouTube and the project’s documentation is in wiki format.
Download: [ Golems Universal Constructor 0.54.4 ]