Popppy
Population Propogation in Python. Simulate births, marriages, deaths
..., for anyone curious about near-future demographics or CO2 emissions, or curious amateurs. Since it's Open Source (<2000 lines of Python code) you can make your own changes.
It runs from the command line and should run on any (MS WIndows, Linux/Unix/Mac OSX) platform running Python 3. A non-Python MS Windows pre-compiled Popppy executable/binary is included for those who just want to run it without having the bother of installing Python 3.x or not wanting to change the source code.