PUPS/P3 facilitates development of multi-process multi-host computations by providing tools to emulate colonies of homeostatic organisms. It permits persistent computation, homeostatic resource protection, and asychronous interprocess communication.
OpenCity is another 3D city simulator. You can build residential, commercial and industrial zones then supply them with necessary goods and watch them grow up. Version 0.0.6stable is now available for download. Any feature request/bug report is welcome
Sakura is a Knowledge Navigator and User Interface for UNIX, which implements HyperMedia and its own windowing and packing system, both in the main program and in an extensive API for Tcl and other languages.