stackoverflow clone script OSQA is an open source and easy to use social question and answer system that provides wiki-like features and a voting system. OSQA can be used as an interactive FAQ system for websites and web applications.

Qwench is a PHP/mySQL based StackOverflow clone.

This is Askbot project - open source Q&A system - askbot-devel repository is open to anyone who wants to help develop Askbot - Askbot is based on code of CNPROG

A Q&A site helps your online community to share knowledge. No matter what your area of interest, people with questions can get super answers fast.

An open source Q&A(question and answer) eco-system

stackoverflow-like app written in ruby, mongomapper and mongodb Question Vote script.