aivest.com is a hobbyist project designed and maintained by Tim van der Horst, https://www.pqconsulting.de
It was started in 2010. It is not open source (yet - I am thinking about making it an open source project).
The aivest idea is that there are some quantitative methods that everyone can use to structure a well balanced stock portfolio. I love stocks, I think investing in stocks makes a lot of sense. I am also using aivest.com to test new technologies.